While we discussed that rivers flow 'downhill' regardless of cardinal direction, the Casiquiare Canal in Venezuela is a geographical freak of nature. It is a natural waterway that connects two of the world's largest river systems: the Orinoco and the Amazon. It is the largest natural 'bifurcation' in the world. The Casiquiare takes water from the Orinoco River and carries it southward to the Rio Negro, which then flows into the Amazon. This means that water from one major basin 'leaks' into another, effectively making a large part of South America a giant island. It is one of the few places on Earth where a traveler can move between two distinct major river basins without ever leaving the water.