Mars is a dead world, showing the barest hints of geological activity today. But in the distant past, it was a tumultuous planet that spawned the largest volcano in the solar system. Olympus Mons ...

Take a tour of the space volcanoes on other planets and moons across the Solar System, and find out how they differ from ...

Scientists are still trying to figure out. Like Earth and Venus, Mars has mountains, valleys, and volcanoes, but the red planet’s are by far the biggest and most dramatic. Olympus Mons ...

Researchers used gravity field data from satellites to probe the internal structure of Mars. The identified dense structures could either be volcanic formations or remnants of ancient impacts.