Built in 1010 AD by Raja Raja I, a great Chola ruler, the Brihadeeswara (Brihadishwara ) Temple has been listed as a World Heritage Site by UNESCO. Its outer fortifications were later put up by the Nayak rulers, for extra protection. Thanjavur's most prominent landmark, it is also known as Peruvudaiyar Kovil or the ‘Big Temple’. It is a fine example of Chola architecture and was constructed using some of the most advanced techniques of that time. The temple houses inscriptions that give detailed accounts of the town and its life from a 1,000 years ago. Dedicated to Lord Shiva, the temple is a towering structure at 212 ft, and houses one of India's tallest shivlings, about 13 ft high. Another highlight is India's second-largest monolith of Nandi (bull god), which is 12 and a half ft high, eight ft long and five ft wide. It stands at the entrance of the temple, as a protector of the land. The Big Temple celebrated its 1000th year of construction in 2010. The major festival celebrated here is Maha Shivaratri during the second week of February.