Ngorongoro Crater is an extinct volcanic caldera in the Eastern (Great) Rift Valley, northern Tanzania. It is the world’s largest intact and unfilled volcanic caldera, measuring between 10 and 12 miles (16 and 19 km) across and having an area of 102 square miles (264 square km). The prehistoric volcano would have been a large mountain before it collapsed, rising to around 4,500 to 5,800 meters (14,800 to 19,000 feet) above sea level. It is the largest and most scenic crater in the Ngorongoro Conservation Area, with a large concentration of wildlife.