Images reveal where lava broke through the wall of a Martian crater and began filling it up

At a fundamental level, Mars is a volcanic planet. Its surface is home to the solar system's largest extinct volcano, Olympus Mons, and another trio of well-known volcanoes at Tharsis Montes. And those are just the highlights: there are many other volcanoes on the surface. Though that volcanic activity ceased long ago, the planet's surface tells the tale of a world disrupted and shaped by powerful volcanic eruptions.