Nandi Hills or Nandidurg (Anglicised forms include Nandidrug and Nandydroog) is an ancient hill fortress of southern India, in the Chikkaballapur district of Karnataka state. It is located just 10 km from Chickballapur town and approximately 60 km from the city of Bangalore. The hills are nestled between the neighboring towns of Nandi, Muddenahalli, and Kanivenarayanapura. The hills are traditionally held as the origin of the Arkavathy river.
Know more about Nandi Hills in Wikipedia
Source: ebay.com