Kalavantin Durg, located very close to Panvel (About 17 Kms). It is a relatively difficult trek, with the monsoon rains that make the views breathtaking and the climb nerve wrecking.
The base village to start this trek is the Thakurwadi village from where one can go to both Prabalgarh Fort and Kalavantin Fort.
The trek is fun especially during the monsoons (June – Sep) as the greenery and weather is the best then. It also makes the trek far more difficult due to the slippery terrain.