Olympus Mons the -diameter Pangboche crater (). The craters are notable for being two of several suspected source areas for shergottites, the most abundant class of Martian meteorites. As a shield volcano, Olympus Mons resembles the shape of the large volcanoes making up the Hawaiian Islands. The edifice is about wide. Because the mountain is so large, with complex structure at its edges, allocating a height to it is difficult. Olympus Mons stands above the Mars global datum, and its local relief, from the foot of the cliffs which form its northwest margin to its peak, is nearly (a little over twice
Highest unclimbed mountain Highest unclimbed mountain An unclimbed mountain is a mountain peak that has yet to be climbed to the top. Determining which unclimbed peak is highest is often a matter of controversy. In some parts of the world, surveying and mapping are still unreliable, and there are no comprehensive records of the routes of explorers, mountaineers and local inhabitants. In some cases, even modern ascents by larger parties have been poorly documented and, with no universally recognized listing, the best that can be achieved in determining the world's highest unclimbed peaks is somewhat speculative. Most sources indicate that Gangkhar Puensum ()