After all, it is one that was introduced in the United States into the Mississippi River near Mississippi, and has managed to swim upstream all the way across our country to the point where that river meets up with the Illinois River.

FORBES: Will Chinese Eat 'Wild Mississippi River Fish'?

Strel plans to swim across the Grand Canyon , along 1, 000 miles of the freezing Mackenzie River in Canada, and the length of the 2, 000-mile Volga .

BBC: What adventures are actually left?