This fort is situated west of Hyderabad. The outer wall of this fort is 10km long. Many famed diamonds, including The Hope Diamond & The Regent Diamond, are believed to have been excavated from the mines surrounding this fort. Identify this fort.

Golkonda Fort is the correct answer as it is situated west of Hyderabad and the surrounding Kollur Mine was the source of famous diamonds including the Hope Diamond and Regent Diamond. The fort's outer walls stretch approximately 10 kilometers, making it one of the largest fortified complexes in India. Gandikota is known as the Grand Canyon of India, while Penukonda and Khammam are different historical forts in Andhra Pradesh.