two tall wall like structures stand out greatly from the surrounding
area. They look like a buries entrance to an abandoned base. These are
really cool looking structures. Perhaps if we take the diameter of
Paracelsus crater which the wall is in, then we can find the walls size.
Wiki says Paracelsus crater is 83km, so we can make an estimate that
these walls are about .35-.45km across. That a good size structure.