Ngorongoro Crater is a massive, 20 km-wide caldera that has become a haven for wildlife. It has no human settlements. From the rim of the crater, you're too far away to see any animals, but when you drive down into the crater on a safari drive, you discover the area is teeming with all kinds of wildlife. In fact, the crater has Africa's highest density of lions. It's also home to 7,000 wildebeest, 6,000 black-spotted hyenas, and 4,000 zebras.