Riemann (Moon)

Named after Georg Friedrich Bernhard Riemann - German mathematician (1826-1866).

Riemann is a lunar crater that is located near the northeastern limb , and can just be observed edge-on when libration effects bring it into sight. It lies to the east-northeast of the large walled plain Gauss. To the southeast, beyond sight on the far side, is the crater Vestine. This is a heavily battered and eroded formation that is only a remnant of its former self. (wikipedia entry)

A crater is a circular depression likely created by an impact event. On the Moon they are named after deceased scientists, polar explorers, astronauts or cosmonauts.