The fort of Kalavantin Durg can be found near the city of Mumbai, in the Western Ghats or the Sahyādri Mountains, in India.
It is believed that the Fort was built around the time of Buddha or around or before 500 BCE. The fort is at an elevation of over 2,000 feet. It lays just opposite of Prabalgad and is visible from the Mumbai-Pune Expressway. According to legend it was built for a queen named Kalavantin but that really seems to be all that anybody knows. The steps leading up to the fort were cut into the rock of the hill, a very impressive feat. At the top of Kalavantin Durg you can see the Peb, Chanderi, Matheran, Karnala, and Ershal forts. The city of Mumbai itself can also be seen.
In the Machi-Prabal village, the Adivasi Peopl dance on top of the Kalavantin Fort on every Shimga Festival of Holi. The fort is a part of their custom and heritage.
Technically this fascinating place is abandoned in the sense that it is not used for its original purpose, but it gets visits from tourist and locals often and is easily accessible from the Mumbai-Pune Expressway.
You can find this impressive fort with these coordinates. 18.98282,73.220369.
Image 1 used under Creative Commons License Attribution No Derivs 2.0 Generic. Image 1 by [s e l v i n] / Flickr.
Image 2 used under Creative Commons License Attribution Share Alike 2.0 Generic. Image 2 by Rohit Gowaikar / Flickr.