Inside the Crater

A zebra walks through the lush grass inside Tanzania's Ngorongoro Crater. Unlike zebra and wildebeests outside the crate, animals inside the crate do not take part in the annual migration.

The crater is the world's largest inactive, intact and unfilled volcanic caldera. The crater was formed when a volcano erupted and collapsed 2 to 3 million years ago. It is 2,000 feet deep. The crater floor is mostly open grasslands, and is home to a variety of animals, including Cape buffalo, elephants, zebras, lions and other animals except for giraffes.