Mars has the deepest canyon in the solar system, the Vallis Marinaris, measuring 4.2 miles (6.7 km) deep, 300 miles (500 km) wide, and 2,800 miles (4,500 km) long.
The nearby canyons average about 1.8 miles (3 km) deep.
The deepest crater on Mars is the Hellas Planitia, some 3.6 miles (6 km) deep.
Mars’s Vallis Marinaris measures 4.2 miles (6.7 km) deep; Arizona’s Grand Canyon is only 1 mile (1.6 km) deep.
