Taragarh Fort, the fort of Ajmer, seat of the Chauhan rulers, is claimed to be the first hill fort of Asia, built at a time when the Aravalli mountain ranges were above the snowlines. This gives it the reputation of being one of the oldest hill forts of the world, and it is definitely the oldest among the hill forts in India. It was built by King Ajaypal Chauhan on the summit of Taraga?h Hill, overlooking Ajmer; its thick battlements run along its brow, completely enclosing the table-land. The walls are two miles (3 km) in circumference, and the fort can only be approached by steep and very roughly paved slopes. When it came into the hands of the British Raj, the fort was dismantled by order of Lord William Bentinck, and was converted into a sanatorium for the troops stationed at the British cantonment town of Nasirabad.