Sri Padmanabhaswamy Temple, Thiruvananthapuram

The Sri Padmanabhaswamy Temple in Thiruvananthapuram is the principal shrine of the erstwhile Travancore royal family, who continue to hold ceremonial trusteeship. The deity, Lord Padmanabhaswamy, is a 5.5-metre reclining Vishnu visible only through three doors — one for the head, one for the body, and one for the feet — and is worshipped in his Anantashayanam form on the serpent Adishesha. The temple's vault B, the only sealed chamber yet to be opened, is widely believed to contain treasure that would make the temple the wealthiest religious institution on Earth (estimated $1+ trillion in declared assets from the other vaults alone). The Supreme Court of India has barred its opening pending royal family arguments. The temple itself dates from the 8th century, with major additions in the 16th–18th centuries by the Travancore kings. Strict dress code: men must wear a mundu and remove shirts; women wear sarees or salwar.