Seen here is a lunar mountain range that stretches 600 km in length. Called Montes Apenninus, it forms the south-eastern border of Mare Imbrium.
Montes Apenninus was formed ~3.8 to 3.9 billion years ago when the basin of Mare Imbrium was excavated as a result of an impact by an asteroid-sized body. The impact uplifted nearby crustal material to form the arc-shaped mountain range.
Montes Apenninus is home to the Moon’s tallest mountain Mons Huygens, which soars 5.5 km high, though its not the highest point on the Moon. On the east end of the mountain range lies the mountain Mons Hadley Delta, near which NASA’s historical Apollo 15 mission landed. From Apollo 15 rock samples, we know that the impact that formed Imbrium basin happened several hundred million years before the volcanic eruptions that filled the basin.
Montes Apenninus is a part of a distinct geological feature we see on the Moon called multi-ring impact basins. Landing in such regions is key to understanding the formation of multi-ring basins and how they affect the Moon’s geological evolution, as well as that of other planetary bodies.