Of the eight lunar features identified as rupes or scarp, perhaps the two most dominant are Rupes Altai and Rupes Recta. The image of Rupes Altai below was taken near the terminator of a nineteen-day old moon and features very good detail surrounding the scarp including fine-level detail within the 427-km long scarp itself. This formation lies to the west of Mare Nectaris and is believed to be between 3.82 and 3.95 billion years old. Its northern-most point is around the well-known crater Catharina and its termination point is just before crater Piccolomini.

Note: Further information in relation to Rupes Altai is available in S&T (Jun/2004: 68-69).