Columbus (Mars)

Named after Christopher Columbus - Italian explorer (1451-1506).

The discovery of sulfates and clay minerals in sediments within Columbus Crater are strong evidence that a lake once existed in the crater. Research with an orbiting near-infrared spectrometer, which reveals the types of minerals present based on the wavelengths of light they absorb, found evidence of layers of both clay and sulfates in Columbus crater. This is exactly what would appear if a large lake had slowly evaporated. (wikipedia entry)

A crater is a circular depression likely created by an impact event. On Mars large craters are named after deceased scientists, writers and others who have contributed to the lore of Mars. Small creaters (less than 60km) are named after small towns and villages.