Water worlds
Follow the Amazon, Nile, Danube, Mekong and Ganges from their tributaries to the sea.
Sources: Natural Earth · HydroRIVERS
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A river’s course is longer than the direct distance between its endpoints. Here you can straighten five mapped segments to compare those distances.
The comparison uses selected Natural Earth centerlines. The basin tours below use HydroRIVERS to show tributaries and river mouths.
Compare five mapped river segments, then unfold their geometry. The amber dashed line joins the endpoints; the green line follows the river.
Straighten a mapped segment to compare its length with the direct distance between its endpoints.
Each geographic shape is fitted separately. Pull it straight to compare on one distance scale.
Mapped segment length · longest connected part in the source, not the full river.
Natural Earth 1:10m centerlines. Each measurement follows the longest connected part of the named feature, not the complete source-to-mouth river. Gaps and tributaries are not joined. Distances use the source vertices on a sphere; fine meanders are generalized. The animation is a reading aid, not simulated water flow.
| River | Region | Source | Network group |
|---|---|---|---|
| Amazon | South America | Natural Earth · 1:10m river centerlines | Main courses |
| Nile | Northeast Africa | Natural Earth · 1:10m river centerlines | Main courses |
| Danube | Europe | Natural Earth · 1:10m river centerlines | Main courses |
| Mekong | Southeast Asia | Natural Earth · 1:10m river centerlines | Main courses |
| Ganges | South Asia | Natural Earth · 1:10m river centerlines | Main courses |
Sunlight catches looping channels of the Amazon. Pale traces and isolated pools mark older paths across the floodplain. NASA / ISS Expedition 52 · ISS052-E-39523 · 9 August 2017.
A short field recording of flowing water in a Muir Woods stream. This is a listening interlude from California, not a recording of the five mapped rivers.
National Park Service · recorded at Muir Woods, California · no claim to original U.S. Government works
Sounds of water flowing in a stream.
Five selected river courses.
Begin with the Amazon. The selected linework stretches across northern South America, bending toward the Atlantic. At this scale, a river becomes a way to read the width of a continent.
Only the centerline sections named Amazonas in the source are highlighted. This is not a map of the entire Amazon basin or all its tributaries.
Source: Natural Earth · rivers and lake centerlines · 1:10m
Follow the Nile north. Against the surrounding land, the highlighted course makes a long corridor toward the Mediterranean.
The source separates several named parts of the Nile system. Here we show the sections called Nile, so the headwater network is not a complete drainage map.
Source: Natural Earth · rivers and lake centerlines · 1:10m
The Danube draws a different kind of journey across Europe. Follow its bends on the way toward the Black Sea and notice how much information a single line can carry.
Pan freely, then return to the next scene. The story changes which river is visible while keeping the same geographic context.
Source: Natural Earth · rivers and lake centerlines · 1:10m
In Southeast Asia, the Mekong’s course invites another north-to-south reading of the landscape. The line winds through a broad region before reaching the sea.
At a closer scale, channels, banks and seasonal change would need more detailed data. This map is an invitation to follow a route, not a navigational chart.
Source: Natural Earth · rivers and lake centerlines · 1:10m
Our last journey follows the Ganges across northern South Asia. As the map moves, notice how each river has acquired its own visual rhythm: long sweeps, sharp turns, branching ends.
What is missing can be as instructive as what is shown. A selected centerline cannot stand in for a whole living river system.
Source: Natural Earth · rivers and lake centerlines · 1:10m
| River | Region | Source | Network group |
|---|---|---|---|
| Amazon | South America | Natural Earth · 1:10m river centerlines | Main courses |
A river mouth connects to a whole upstream network. Tributaries join a larger river; distributaries carry water away from it across a delta. Follow the Amazon below, then open another basin’s optional tour if you want to compare. The scenes reveal selected connections in stages. These scenes use HydroRIVERS classical orders 1–3, which count outward from the main stem. This differs from Strahler order, which starts at the headwaters. Smaller tributaries are filtered out, and the routed network does not resolve all delta distributaries.
Follow the main stem (classical order 1), reveal its tributaries in blue (order 2), then their tributaries in amber (order 3). The colors show HydroRIVERS network order, not discharge. Smaller tributary reaches are omitted.
Start with HydroRIVERS’ order-1 backbone through this connected basin. In the next scene, look for the tributaries that bring other parts of the landscape into its journey toward the outlet. The backbone may cross several named rivers.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
The Amazon’s lower course gathers water from a network stretching far beyond the main line. Follow the blue tributaries toward the main stem: each confluence brings another upstream landscape into the story. This view keeps the larger branches, with at least 25,000 km² of land draining to each retained tributary reach.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
Now follow the amber branches into the blue tributaries. HydroRIVERS classifies these as order 3: they feed order-2 tributaries, which in turn feed the main stem. The larger rivers are themselves meeting places. The same upstream-area threshold keeps this continental view readable.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
At the Atlantic, the narrow idea of a single river gives way to a broad estuary and a complex river mouth around Marajó. The water arriving here has travelled through many upstream branches. These regional centerlines show that larger relationship, but do not resolve the tidal channels or draw the delta’s boundary.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
| River | Source | Network group | System | Level | ORD_CLAS | MAIN_RIV | Reach count | Minimum upstream area (km²) |
|---|---|---|---|---|---|---|---|---|
| Amazon network · main stem | HydroRIVERS v1 · WWF / HydroSHEDS · Lehner & Grill (2013) | Amazon · 0 | Amazon | 0 | 1 | 60443230 | 2345 | 0 |
Follow the main stem (classical order 1), reveal its tributaries in blue (order 2), then their tributaries in amber (order 3). The colors show HydroRIVERS network order, not discharge. Smaller tributary reaches are omitted.
Start with HydroRIVERS’ order-1 backbone through this connected basin. In the next scene, look for the tributaries that bring other parts of the landscape into its journey toward the outlet. The backbone may cross several named rivers.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
The White Nile and Blue Nile meet at Khartoum. Reading upstream from their meeting point turns the long northward corridor into two distinct journeys. HydroRIVERS chooses one continuous route as its order-1 backbone; blue branches feed that route. The hierarchy describes network connections, not the importance of one named river over another.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
The amber reaches add one more step upstream: tributaries feeding tributaries. Only reaches with at least 5,000 km² draining into them are retained at these two tributary levels. Smaller streams still belong to the basin even where the map leaves them out.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
North of Cairo, the Nile spreads toward the Mediterranean. Tributaries gather water into a main course upstream; distributaries divide that course near its mouth. Keep that reversal in mind as you move from the basin view to the delta. This generalized map cannot show every distributary or changes in flow caused by dams and irrigation.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
| River | Source | Network group | System | Level | ORD_CLAS | MAIN_RIV | Reach count | Minimum upstream area (km²) |
|---|---|---|---|---|---|---|---|---|
| Nile network · main stem | HydroRIVERS v1 · WWF / HydroSHEDS · Lehner & Grill (2013) | Nile · 0 | Nile | 0 | 1 | 10047863 | 1935 | 0 |
Follow the main stem (classical order 1), reveal its tributaries in blue (order 2), then their tributaries in amber (order 3). The colors show HydroRIVERS network order, not discharge. Smaller tributary reaches are omitted.
Start with HydroRIVERS’ order-1 backbone through this connected basin. In the next scene, look for the tributaries that bring other parts of the landscape into its journey toward the outlet. The backbone may cross several named rivers.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
The Sava and Tisza join the Danube in its middle basin. Farther downstream, the Prut joins shortly before the delta. The blue order-2 network shows how valleys across Europe feed a common main stem. Tributary reaches are retained once their upstream drainage area reaches 2,000 km².
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
The amber lines reveal a second step upstream from the Danube: order-3 reaches feeding order-2 tributaries. Follow each through its downstream connection. A valley away from the main course still belongs to the same journey toward the Black Sea. The colors follow HydroRIVERS order classes rather than a hand-picked list of river names.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
At the Black Sea, the Danube divides among the Chilia, Sulina and Sfântu Gheorghe branches. The map’s regional centerlines are a guide to location, not a complete inventory of these delta channels. The tributaries behind you and the distributaries ahead play opposite roles: gathering, then spreading.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
| River | Source | Network group | System | Level | ORD_CLAS | MAIN_RIV | Reach count | Minimum upstream area (km²) |
|---|---|---|---|---|---|---|---|---|
| Danube network · main stem | HydroRIVERS v1 · WWF / HydroSHEDS · Lehner & Grill (2013) | Danube · 0 | Danube | 0 | 1 | 20498112 | 712 | 0 |
Follow the main stem (classical order 1), reveal its tributaries in blue (order 2), then their tributaries in amber (order 3). The colors show HydroRIVERS network order, not discharge. Smaller tributary reaches are omitted.
Start with HydroRIVERS’ order-1 backbone through this connected basin. In the next scene, look for the tributaries that bring other parts of the landscape into its journey toward the outlet. The backbone may cross several named rivers.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
The wider Mekong network brings together landscapes on both sides of the main river. The Mekong River Commission describes the Sekong, Sesan and Srepok together as the 3S basin. Here, the blue lines show HydroRIVERS order-2 tributaries; retained reaches have at least 5,000 km² of upstream drainage area.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
Reveal the amber order-3 branches and follow their paths into the blue tributaries. The network is connected by downstream reach IDs, so each retained branch has a route back to the modeled outlet. Smaller branches are filtered out, while the junctions between the visible rivers are preserved.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
The Mekong reaches the sea through a delta in southern Viet Nam. What happens upstream can change the water and sediment reaching this lowland landscape. Read the highlighted lines as connections across the basin, not as predictions of flooding, sediment delivery or the position of today’s banks.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
| River | Source | Network group | System | Level | ORD_CLAS | MAIN_RIV | Reach count | Minimum upstream area (km²) |
|---|---|---|---|---|---|---|---|---|
| Mekong network · main stem | HydroRIVERS v1 · WWF / HydroSHEDS · Lehner & Grill (2013) | Mekong · 0 | Mekong | 0 | 1 | 41392598 | 1619 | 0 |
Follow the main stem (classical order 1), reveal its tributaries in blue (order 2), then their tributaries in amber (order 3). The colors show HydroRIVERS network order, not discharge. Smaller tributary reaches are omitted.
Start with HydroRIVERS’ order-1 backbone through this connected basin. In the next scene, look for the tributaries that bring other parts of the landscape into its journey toward the outlet. The backbone may cross several named rivers.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
The Ganges and Brahmaputra share a downstream network. This scene selects their connected HydroRIVERS basin rather than treating the Brahmaputra as a minor Ganges tributary. Order 1 is the dataset’s continuous backbone through that shared network; it does not necessarily follow the river named Ganges throughout. Blue reaches feed that backbone.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
The amber branches reveal another level of connection across the shared basin. At orders 2 and 3, reaches with less than 5,000 km² of upstream drainage area are omitted. Read the colors as positions in a routed network, not a ranking of cultural importance, river length or water volume.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
The Ganges, Brahmaputra and Meghna meet in the Bengal delta system before reaching the Bay of Bengal. The selected network follows one modeled downstream route, which ends before resolving the wider tidal estuary. It cannot represent all the delta’s distributaries: each HydroRIVERS reach has a single downstream connection. This closer view places the upstream network in its coastal setting.
Source: HydroRIVERS v1 · classical orders 1–3 · WWF / HydroSHEDS · Lehner & Grill (2013)
| River | Source | Network group | System | Level | ORD_CLAS | MAIN_RIV | Reach count | Minimum upstream area (km²) |
|---|---|---|---|---|---|---|---|---|
| Ganges network · main stem | HydroRIVERS v1 · WWF / HydroSHEDS · Lehner & Grill (2013) | Ganges · 0 | Ganges | 0 | 1 | 41067217 | 1411 | 0 |
The comparison measures selected connected segments, not the full length of each river system. The basin tours add tributaries, but omit smaller reaches.
Download the data and consult the source notes before using these lines at a more detailed scale.
Natural Earth · rivers and lake centerlines The original five named river features used in the unfolding comparison and opening tour. Public-domain centerline geometry.
Natural Earth · public-domain terms The source geometry may be reused and adapted.
HydroRIVERS v1 · WWF / HydroSHEDS Lehner, B. and Grill, G. (2013), Global river hydrography and network routing, Hydrological Processes 27: 2171–2186, doi:10.1002/hyp.9740. Derived from HydroSHEDS © World Wildlife Fund, Inc. (2006–2022); all rights reserved. Basin filtering, chain merging and simplification by Atlas.
HydroSHEDS license and terms This product, Atlas Storymaps: The long way to the sea, incorporates data from the HydroSHEDS version 1 database which is © World Wildlife Fund, Inc. (2006–2022) and has been used herein under license. WWF has not evaluated the data as altered and incorporated within Atlas Storymaps: The long way to the sea, and therefore gives no warranty regarding its accuracy, completeness, currency or suitability for any particular purpose. Portions of the HydroSHEDS v1 database incorporate data which are the intellectual property rights of © USGS (2006–2008), NASA (2000–2005), ESRI (1992–1998), CIAT (2004–2006), UNEP-WCMC (1993), WWF (2004), Commonwealth of Australia (2007), and Her Royal Majesty and the British Crown and are used under license. The HydroSHEDS v1 database and more information are available at https://www.hydrosheds.org.
ICPDR · Danube River Basin Background on Danube tributaries and delta branches.
Mekong River Commission · Geography Background on the Mekong basin, 3S tributaries and delta.
FAO · Ganges–Brahmaputra–Meghna river basin Background on the shared delta and river confluences.
The river remembers NASA / ISS Expedition 52 · ISS052-E-39523 · 9 August 2017
Listen closer National Park Service · recorded at Muir Woods, California · no claim to original U.S. Government works
How this edition was made The original Natural Earth comparison geometry is unchanged. Network scenes use HydroRIVERS v1, selected by MAIN_RIV and ORD_CLAS 1–3. Order 1 is the dataset backbone, not necessarily one named river. Tributary reaches require upstream areas of 25,000 km² (Amazon), 2,000 km² (Danube), or 5,000 km² (Nile, Mekong and the shared Ganges–Brahmaputra basin). NEXT_DOWN closure and endpoint agreement are checked before merging chains and simplifying at 0.01 degrees; retained confluences are preserved and coordinates rounded to five decimal places. Grouped map features retain classical order, basin ID and reach count. The one-downstream-link model does not describe every delta distributary or tidal channel. HydroRIVERS is used under the HydroSHEDS license; obtain its source data from the official product page. The story download contains only the five public-domain Natural Earth comparison features. The unfolding comparison measures the longest connected part of each named river on a sphere of radius 6371.0088 km; disconnected parts are not joined. Geometry is resampled only for display. The straightened state shares a distance scale; the geographic state fits each river independently. This is not a flow or discharge model.
Data retrieved 2026-09-13. Native maps and original narrative by Atlas Storymaps. Source data: Natural Earth · HydroRIVERS. Natural Earth and USGS-produced source data are public domain. Basemap and terrain providers are credited on each map.