Nov 16, 2011
One good example is the Marines Canyon that runs through a huge part of Mars. It's 4000 km long, which is twice as long as the Japanese archipelago. The width reaches 700 km in some places, the and it is 7 km deep. The Grand Canyon is just 30 km wide and 2 km deep. It's so big, you won't even realize you're in a canyon even if you're standing in it!