No. 4 The Orinoco River
Running through South America at about 1330 miles in length, it has over 200 branches and several waterfalls. It is very difficult to navigate because of its rapids, and is surrounded on both sides by dense rainforest, especially when crossing through Venezuela and Colombia. The Orinoco River is prone to flooding and hinders nearby inhabitants. Moreover, it experiences a coastal upswelling, posing threats to locals.
