Image: Frozen Lake Sharpe, South Dakota

The Missouri River rises in the Rocky Mountains of western Montana, and flows generally to the southeast for 3,767 kilometers (2,341 miles) to its confluence with the Mississippi River north of St. Louis, Missouri. It is ...

Take a trip to the largest lake on Mars

Mars once hosted a lake larger than any on Earth. The broken-down and dried-up remnants of this ancient lakebed are shown here in amazing detail by ESA's Mars Express.

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