Lord Someshwara appeared to him in a dream, revealing the existence of hidden treasure and told him to build the temple dedicated to him with it. Another ancient temple is the Gavi Gangadhareshwara Temple, in the Chola style of architecture, which is a protected monument under the Karnataka Ancient and Historical Monuments, and Archaeological Sites and Remains Act 1961. It is a cave temple dedicated to Lord Shiva. It is one of the best architectural monuments depicting a monolithic idol of Lord Shiva made of granite, a rare idol of Agni, the God of fire and monolithic exquisitely carved four pillars inside the cave. The cave temple is also stated to be a fine piece of Indian rock-cut architecture of the 9th century. In the 16th century, Kempe Gowdas added grandeur to the temple by building the frontage to the cave temple with Gopuras (towers), large tridents, discs known as Suryapana and Chandrapana representing the Sun and the Moon, a damaru (drum) and two fans (all pictured in the gallery). Another interesting astronomical feature which attracts thousands of devotes to the temple on Makar Sankranti day in January is of sun rays passing between the horns of the Nandi (bull), located outside at the entrance to the temple, which lights the idol of Shiva inside the cave. A famous temple built in the 16th century during the rule of Kempegowdas, is the Bull temple or the Nandi Temple (‘Nandi' in Sanskrit means ‘joyful') made of granite. This temple built in 1537 on a hill top with a porch in the Vijayanagara architectural style is named after the large granite Nandi monolith placed on a plinth in the temple shrine. The temple is exclusive for the worship of the sacred bull in Hinduism, known as Nandi, Lord Shiva's vahana, or animal mount. Nandi idol at this temple is said to be one of the largest in the world, with height of about and length. Temples for Dodda Ganapathy (huge Ganesha -– height & wide) and for Lord Shiva, a little above the Ganesha temple, are also located at the foot of the hill. A groundnut fair called Kadalekay Parishe in Kannada language, which is linked to a popular folklore legend, is held by farmers every year during November to thank Nandi for the good yield of this crop and to seek further blessings.