Tags: Crater.
The Caloris Basin also called Caloris Planitia is a large impact crater on Mercury about 1550 km (960 mi) in diameter one of the largest impact basins in the solar system. Calor is Latin for heat and the basin is so-named because the Sun is almost directly overhead every second time Mercury passes perihelion. The crater discovered in 1974 is surrounded by a ring of mountains approximately 2 km (1.2 mi) tall.
