Rima Hyginus & Hyginus crater

Rima Hyginus is an unusual formation with an average width of 3 km and length of 220 km. It is bisected by crater Hyginus (10.6 km), which is actually a caldera of volcanic origin. It is one of the few 'craters' of non-impact origin. The rille and crater were probably formed by magma that collected under the surface, forming a 'lava tube' which eventually collapsed, forming Hyginus and the many smaller craters dotted along the rille. This is a relatively "young" feature on the Moon. The Northern end of the complex rille system Rimae Triesnecker is visible in the top of the image.