For the first lunar landing, Mare Tranquilitatis (The sea of Traquillity)was the site chosen because it is a relatively smooth and level area...the LM had to be manually piloted by Neil Armstrong to avoid a sharp-rimmed ray crater measuring some 180 meters across and 30 meters deep known as West. The LM landed safely some 6 km from the originally intended landing site.
From Apollo 11 Landing Site
Map of Moonwalk Apollo 11
