Which city is famous for the Chithirai festival, one of world’s longest festivals?

Madurai
The Chithirai festival is one of the biggest celebrations in Madurai, Tamil Nadu. It re-enacts the wedding of Lord Sundareswarar (Lord Shiva) and Goddess Meenakshi (Lord Vishnu’s sister). The festival begins on the fifth day of the bright half of the Tamil month Chitrai (April/May). In 2015, the date of the Chithirai festival is from April 21 to May 7.