Is Rumker the Moon's biggest dome? How about the Aristarchus Plateau? What about the Gardner Megadome, a structure I named in The Modern Moon, and shown in the overview image above (circled on mouseover)? In fact, are any of these landforms domes, other than in a strict topographic sense? The Gardner Megadome is very rough textured and about 70 km wide and 300-400 meter above the nearby edge of Mare Tranquillitatis. Its summit seems to hold an irregular depression with what looks to be a channel running down slope to the south. Is this a giant pit crater on a giant dome? Unfortunately, most available orbital and telescopic photos don't clarify the interpretation. High resolution, low sun images are needed - will someone get them this lunation?