Mare Crisium

Mare Crisium is a lunar mare located in the Moon's Crisium basin, northeast of Mare Tranquillitatis, with a diameter of 556 km and an area of 176,000 square kilometers. It is a basin of Nectarian age, formed by the flooding of basaltic lava that filled an ancient asteroid impact. The mare has a flat floor with a ring of wrinkle ridges and features such as Promontorium Agarum, Yerkes, and Lick, as well as the crater Picard and the ray system of the crater Proclus. A mass concentration was identified in the center of Mare Crisium from Doppler tracking of the Lunar Orbiter spacecraft in 1968. The mare has been the site of several notable events, including the crash-landing of the Soviet Luna 15 probe and the successful collection of a soil sample by the Soviet lunar mission Luna 24. It has also been featured in science fiction works such as Arthur C. Clarke's short story "The Sentinel" and the Warhammer 40k setting.learn more on wikipedia