The Straight Wall, or Rupus Recta, is located in Mare Nubium. It is a 300 meter high fault which stretches from Thebit D, the small crater in the north (3 miles diameter), to a small mountain in the south. South is up-left in this image.
Towards the left facing the Straight Wall is steep crater Birt (10mi)
which has Birt Rille extending 30 miles towards the north, just about seen
in this image in the twilight of the terminator. On the opposite side of
the Straight Wall there is Thebit (35mi) with Thebit A (12mi) in its west
wall, and magnificent 11,000 feet high Arzachel to its north which
features a 4500ft central mountain, seen here just top left of the image