Plato is approximately 61 miles in diameter with walls rising to approximately 6000 ft.
Plato has developed a reputation for various transient lunar phenomenons, including flashes of light, unusual colour patterns, and areas of hazy visibility. These anomaly are likely a result of seeing conditions, combined with the effects of different lighting angles of the Sun.
A couple of interesting sites:-
http://www.ltpresearch.org/plato1.htm
http://www.space.edu/moon/other/plato/PlatoChanges.html
http://www.lpi.usra.edu/resources/mapcatalog/usgs/I701/
http://www.lpi.usra.edu/resources/lunar_orbiter/bin/info.shtml?351
... also, I didn't know that it was the location for Space 1999's 'Moonbase Alpha'.
