Just 20 miles due west of the city is a 10-foot-high glacial moraine that separates the Mississippi and its vast north-south system of tributaries from the Great Lake waterways.

FORBES: A most unromantic river

The Mekong and its tributaries yield more fish than any other river system.

ECONOMIST: The Mekong river

The agreement calls for the water system to be treated as a single complex ecosystem made up of countless tributaries, underground aquifers and smaller lakes all held in the Great Lakes basin.

NPR: Governors Meet on Access to Great Lakes