Wislicenus Crater is an impact crater in the Sinus Sabaeus quadrangle of Mars at 18.4° south latitude and 348.6° west longitude. (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.