Since ancient times, Kolli Hills has always been famous for its medicinal plants. It is believed that the Siddha’s (ancient medicine men) lived, researched and meditated here in the caves inside the sacred groves. Many adventurous men go on trekking expeditions, to the caves where the Siddha’s lived. The caves of Bogar and Agastya are situated near the Agaya Gangai waterfalls, while Korakka Siddha and Kalaanginatha Siddhais deep inside the forest area after 2-3 hrs of steep down trekking along the forest stream.