Eberswalde, formerly known as Holden NE, is a partially buried impact crater in Margaritifer Terra, Mars. It was one of the final four proposed landing sites for the Mars rover Mars Science Laboratory mission. This extraterrestrial geological feature lies situated within the Margaritifer Sinus quadrangle region of Mars. (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.