10. River Nile, Egypt
Admittedly, the muddy waters of the River Nile don’t look like a very inviting place to take a dip, but it’s not the mud that’s the problem. Beneath the surface of the world’s mightiest river lurk the most dangerous of all crocodiles – the Nile crocodile. There are some half a million of these highly aggressive predators in the region and, if that’s not enough, the river is also full of piranha-like tiger fish. Stick to the hotel pool.
