The Invincible - Gwalior fort

As per ASI site, the history of the Fort goes back to the fifth century AD or perhaps still earlier. The old name of the hill as recorded in ancient Sanskrit inscriptions is Gopagiri. It has witnessed varying fortunes of the Guptas, Hunas, the Pratiharas, the Kachhwahas, the Tomars, the Pathans, the Mughals, the English and the Marathas who have left their landmarks in the various monuments which are still preserved. The main monuments which are in the premises of this fort are :- Man Mandir, Teli-Ka-Mandir, Sas Bhau Temple, Badal Mahal, Alamgiri gate, Ganesa gate, Chaturbhuj gate, Rock-cut Jain collosi, Urwai gate, etc. 

Indiaknow site states that for over 100 years this fort has been over looking the city of Gwalior. One of the most invincible forts in India, this imposing citadel has changed many hands. It is built on a hill of sandstone and towers 100 meters from the plain.The outer wall of the fort is almost 2 miles in length and the width varies from one km's to 200 meters. The walls of the fort gives way onto the steep slopes. This fort has been a witness to many battles in the turbulent times as well as festivals in the peace time.