The Orinoco River is one of the longest rivers in South America, flowing 2,250 kilometers through Venezuela and Colombia. It is famous for its Casiquiare canal, a natural waterway that connects the Orinoco system with the Amazon River system—a rare geographical phenomenon where a river splits and flows into two different basins. The Orinoco flows through the Llanos, a vast tropical grassland plain that experiences dramatic seasonal flooding. The river's delta is a massive labyrinth of islands and mangrove forests covering 22,500 square kilometers. The Orinoco is home to the Orinoco crocodile, one of the rarest reptiles in the world, and the Amazon river dolphin. Economically, the river basin contains the Orinoco Belt, which holds some of the world's largest deposits of heavy crude oil. The river remains a primary transport route for the interior of Venezuela, especially for the iron and bauxite industries.