| 100% | THAMES | 6 | River that flows under the Tower Bridge in London |
| 51% | VLTAVA | 6 | River that flows under Prague's Charles Bridge |
| 50% | THAMES | 6 | River under the Tower Bridge |
| 47% | ILLER | 5 | River that flows into the Danube in the center of Ulm |
| 46% | AMES | 4 | River under the London Bridge |
| 43% | DON | 3 | River that rises in the Cairngorm Mountains before flowing east to the North Sea |
| 42% | OISE | 4 | 212 mi. river that flows into the Seine in the suburbs of Paris |
| 41% | EBRO | 4 | River in Spain that flows to the Mediterranean southwest of Tarragona |
| 41% | UGIE | 4 | River in Scotland that flows to the North Sea at Peterhead |
| 41% | DART | 4 | River in Devon that flows into the English Channel at Dartmouth |
| 41% | WESER | 5 | River in Germany that flows to the North Sea at Bremerhaven |
| 41% | OUSE | 4 | River in England that flows to the Wash near King's Lynn |
| 41% | STOUR | 5 | River in Kent that flows into the English Channel at Pegwell Bay |
| 41% | MAIN | 4 | River in Germany that flows through Wurzburg to the Rhine |
| 41% | NILE | 4 | River that flows in East Africa |
| 41% | NEVA | 4 | River that flows by the Hermitage |
| 41% | YSER | 4 | River that flows through the ganzepoot |
| 40% | SPEY | 4 | River in Scotland that flows through the Grampian Mountains to the Moray Firth |
| 40% | ADIGE | 5 | River in North Italy that flows to the Adriatic via Verona |
| 40% | ADIGE | 5 | River in N Italy that flows to the Adriatic via Verona |
| 40% | ADIGE | 5 | River in northern Italy that flows to the Adriatic via Verona |
| 40% | SAVA | 4 | River rising in Slovenia that flows to the Danube at Belgrade |
| 40% | AARE | 4 | River that flows from the Bernese Alps |
| 40% | COLORADO | 8 | River that flows through the Grand Canyon |
| 40% | MOSKVA | 6 | River that flows through the Russian capital |
| 40% | URAL | 4 | River that flows to the Caspian Sea |
| 40% | ELBE | 4 | River in central Europe that flows to the North Sea at Hamburg |
| 40% | SWAN | 4 | River in SW Australia that flows to the Indian Ocean below Perth |
| 40% | SWAN | 4 | River in southwest Australia that flows to the Indian Ocean below Perth |
| 40% | VOLGA | 5 | Longest river in Europe that flows into the Caspian Sea |