The caldera of Ngorongoro marks the ancient walls of a collapsed volcano, which was probably once the size of Mount Kilimanjaro. The circular crater is some twelve miles across, with steep walls of over 2,000 feet. The crater’s rim is 7,500 feet above sea level, the highest altitude we reached on our trip. Because of a permanent supply of water and a precise balance of predator and prey, most of the wildlife remains here year-round. The forest areas are home to herds of bull elephant, including some large, old “tuskers.” There are several prides of lion, and many packs of hyena and jackal.