Mars may have had giant explosive volcanoes in its ancient past that spewed billions of tonnes of rock and ash into the sky.
Scientists believe vast areas of collapsed ground in a region of the planet called Arabia Terra are the vocanoes' remains.
Unlike familiar volcanoes like Etna on Earth, supervolcanoes do not build mountains out of layers of lava.
Their great scale means that when they erupt the whole landscape lets go!
After the eruption, the ground falls back into the void left by all the ejected material, producing a large bowl.
Scientists say such supervolcanoes would have had a big effect on the early evolution of Mars.
It's thought Earth had its own supervolcanoes thousands of years ago. Yellowstone National Park in the United States sits on top of a former supervolcano.