Sachin Joshi, a research assistant at Deccan College Postgraduate and Research Institute, noticed some unusual wall-like structures in the Raigad district of India while perusing Google Earth images. Upon investigations, the walls were discovered to be five forts dating to the 15th and 16th centuries.
Two of the forts have been investigated and are described in Joshi's two books Raigad Jilhyache Durgavaibhav and Ratnagiri Jihyache Durgajignyasa. The additional three are being explored.
“These forts belong to the Vijaynagar empire. The art work on the remnants of the fort proves this. We traced the period of all the discovered forts through archeological evidences like the tanks, wall, coins and pottery that were discovered in the forts,” stated Joshi adding that the documentation of all these forts was essential for conservation purposes.