Olympus Mons, on Mars. The base of this volcano covers a land area roughly equal to the size of the American state of Missouri. The height is almost two and a half times the height of Mt. Everest.
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SW-User
How do they know it's a volcano? It only vaguely resembles one. It could be a plateau with an old meteor strike at the center.
@SW-User It's a "shield volcano". Not the kind that erupts out of the crater. That region of Mars is called the "Tharsis bulge". You can see other , smaller, shield volcanoes in the picture.
The thinking is that this is where, in the distant past, magma was welling up from below the surface and created a large upland area. These shield volcanoes were spots where lava oozed out of their sides building up into the form we see today.
At least, that is the conclusion that geologists have made while studying the area. There are shield volcanoes on Earth as well, and the pattern on Mars looks familiar to geologists. I am not a geologist, so I will defer to them.
