Billions of years ago, a volcanic explosion occurred on Mars which was so massive it actually tilted the planet:
That volcano—the Tharsis volcanic dome—is 96.3 miles by 77.7 miles. When it exploded all those years ago, it disrupted the mantle and crust of the planet (though not the rest of the interior), shifting the whole outside crust up 25 degrees. When the volcano exploded, it did so with a mass of a “billion billion” metric tons of matter, or 1,000,000,000,000,000,000 metric tons.
This explosion may have also lead ultimately to the liquid water which is now evidenced on the planet’s surface.