Tags: Crater.
Main is a lunar crater that is located near the north pole of the Moon. The southern rim of this formation has merged with the larger crater Challis to the south and the level interior floor connects the two craters through a narrower gap. To the north-northwest of Main is Gioja.This formation consists of three overlapping craters that were joined together when the interior floor was resurfaced by lava flows leaving a generally circular formation with outward bulges to the west and northeast.