Mare Tranquilitatis is probably the most well remembered lunar feature from my generation. Who can ever forget listening to those imortal words: "Houston.... Tranquility base here... The Eagle has landed." In the photograph above, the red dot marks the approximate place where Apollo 11 landed and man first set foot on an alien world.
On the lower left (east) edge is Mare Crisium and the bright crater Proclus. The bright crater on the right edge of Mare Tranquilitatis is Dionysius. To the top right (south) is the large, shallow crater Theophilus . Left of Theophilus is Mare Fecunditatis and the pair of bright craters, Messier and Messier A. The bright ray stretching to the west of Messier is commonly nicknamed "the comet". These features are seen better in the image below.