The largest of the lunar mare, Mare Imbrium sits in the
Imbrium basin. The basin material is of the Lower
Imbrian epoch, with the mare material being of the
Upper Imbrian and Eratosthenian epochs. The mare
is lined with mountian ranges called montes to the south.
The crater copernicus is just visible in the bottom of the
photo, while plato is clearly seen on the northern rim.
Sinus Iridum is seen connected to the mare on the
northwestern rim. The crater Archiemedes also visible
in the picture as the lighter circular feature in the
sotheastern region of the mare.