Explore the Ngorongoro Crater, the world’s largest intact and unfilled volcanic caldera. It is indeed the flagship tourism attraction of the Ngorongoro Conservation Area measuring an area of 260sq km and extending about 20km in diameter. The crater is actually a huge caldera of a volcano that collapsed to a depth of 610m about three million years ago. Over the course of time, streams of water made their way down the crater to form little ponds.