The showpiece of the conservation area is undoubtedly the Ngorongoro Crater which was created when a large volcano exploded and collapsed on itself two to three million years ago. It was declared a UNESCO World Heritage Site in 1978 and is the largest intact volcanic caldera in the world.
It measures about 16-19km in diameter, with walls of 400-610m in height. However you measure it, the Crater is a strong candidate for any list of the world’s greatest natural wonders. It is renowned both for its geological splendor, and for being a natural reserve which is home to some of the densest large mammal populations found anywhere in Africa.