mare frigoris

Most of the maria are, to a greater or lesser extent, circular or oval - the result of large impact basins being filled with lava. The Mare Frigoris, seen here in part, is unusual is being a long ribbon of lava.

Photo: Patrice Poyet. The full size original of this can be seen in his large annotated collection of images, Poyet's Celestial HyperBook.

Inconstant Moon