The labelling tells it all in this photo. Particular attention was made to MARE IMBRIUM, the Sea of Rains which fills the Imbrium basin, a depression created in a gigantic impact that affected the Moon's near side. Marking the basin's rim are Montes Appennius. Craters that formed in the time between the basin impact and the lava eruptions that filled it are Archimedes, Plato, and the Bay of Rainbows, Sinus Iridum and the Splendid Copernicus, which formed some 800 million years ago.