Mississippi River | River Thames | Amazon River | Columbia River | Hudson River | Colorado River | Potomac River | river | Ohio River | Missouri River | Delaware River | Murray River | River Tyne | Madeira River | Volga River | River Nene | River Clyde | River Trent | River Severn | Amur River | River Wear | Allegheny River | Red River | Dnieper River | Yarra River | Paraná River | River Tees | Fraser River | Yangtze River | Tocantins River |
These include the Tioyacu River and the subterranean river in the cave of the Huacharos (Cueva de los Huacharos), the natural hot springs at San Mateo, the Laguna Azul lake, the Ahuashiyacu and the Gera waterfalls.
The Fourth River takes its name from a subterranean river beneath Pittsburgh, a city famously sited at the confluence of three rivers: Monongahela, Allegheny, and Ohio.