Ascraeus Mons

Northeastern volcano of the three Tharsis mountains. Pits lie nearby which appear to be the entrance to caves.

Web Pages

 * http://en.wikipedia.org/wiki/Ascraeus_Mons

Cave Entrance Pits Seen in More Detail (Dec 2010)

 * http://news.nationalgeographic.com/news/2010/12/photogalleries/101221-mars-pits-pictures-photos-science-nasa-space-caves/