Wat Ratchanaddaram is a buddhist temple (wat) located at the intersection between Ratchadamnoen Klang and Mahachak Road, in Phra Nakhon district, Bangkok. Meaning Royal Niece, the temple was built to the order of King Nangklao (Rama III) for Mom Chao Ying Sommanus Wattanavadi in 1846.
The temple is best known for the Loha Prasat (โลหะปราสาท), a multi-tiered structure 36 m high and having 37 metal spires, signifying the 37 virtues toward enlightenment. It is the third Loha Prasada (brazen palace) in existence, modelled after the earlier ones in India and Anuradhapura, Sri Lanka. In the past, Loha Prasat was hidden behind an old movie theatre named Chalerm Thai. The theatre were demolished in 1989 as a project to improve scenery along Ratchadamnoen Road.
In 2005, the temple was submitted to UNESCO for consideration as a future World Heritage Site.