Mars amazing facts
1) the largest volcano in the solar system: Olympus Mons (home of the Greek gods) - a height of 27 kilometers (16.7 miles) above the surface of Mars. About 3 times as tall as Mount Everest (29,029 feet). Base 540 kilometers (335 miles) wide and it will cover the entire state of New Mexico!
2) the longest valley in the solar system: Valles Marineris - the valley ranges over 4000 km (2490 miles), and can be as broad as 200 km (125 miles) with depths of up to 7 kilometers (4 miles). Compare this with the Grand Canyon on Earth, which is 446 kilometers (277 miles), 30 km (18 miles) wide and 1.6 kilometers (1 mile) deep. If you put the Valles Marineris on the surface of the Earth, it stretches from New York City to San Diego, California