What’s up with these weird blue patches on Mars? Mashable

A European probe in orbit around Mars just photographed two deep blue patches on the Martian surface, but while they might look like lakes to the untrained eye, don’t be deceived. The spots are actually layers of dark, volcanic rock that appear blue in the photo taken by the European Space Agency’s Mars Express spacecraft. From possible blue auroras to a blue sunset, this photo is just the latest in a series of “blue” images of the red planet.