With three separate hilltop citadels and a 6km perimeter of cliffs and thick walls, the ruins of enormous Gingee Fort rise out of the Tamil plain, 37km east of Tiruvannamalai, like castles misplaced by the Lord of the Rings. It was constructed mainly in the 16th century by the Vijayanagars and was later occupied by the Marathas, Mughals, French and British, then abandoned in the 19th century. The fort's sheer scale, dramatic beauty and peaceful setting make it a very worthwhile stop.
Today, few foreigners make it here, but Gingee is popular with domestic tourists for its starring role in various films. The main road linking Tiruvannamalai and Puducherry cuts between the fortified hills, just west of Gingee town. Of the three citadels, the easiest to reach, Krishnagiri, rises north of the road. To the south are the highest of the three, Rajagiri, and the most distant and least interesting, Chakklidurg (which you can't climb). Ticket offices (with maps) are at the foot of Krishnagiri and Rajagiri.
Remains of numerous buildings stand in the site's lower parts, especially at the bottom of Rajagiri in the old palace area, where the main landmark is the white, restored, seven-storey Kalyana Mahal (Marriage Hall). Just east (outside) of the palace area is the 18th-century Sadat Ullah Khan Mosque; southeast of this lies the abandoned 16th-century Venkataramana Temple.
Hiking Krishnagiri is a one-hour round-trip; Rajagiri (more than 150m above the plain) takes two hours round-trip; allow at least half a day to cover both hills. Most visitors climb Rajagiri, which makes Krishnagiri quieter. Hill-climbing entry ends at 3pm, so sunsets are out. You'll want to start early to beat the heat. Bring water!
Gingee is on the Tiruvannamalai–Puducherry bus route, with buses from Tiruvannamalai (₹37, one hour) every 10 minutes. Hop off at the fort to save a trip back out from Gingee town. A taxi between Tiruvannamalai and Puducherry with a two- to three-hour stop at Gingee costs around ₹3000.