Baltisk Crater is a crater in the Argyre quadrangle of Mars. As craters get larger they usually have a central peak. The peak is caused by a rebound of the crater floor following the impact. (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.