A Buddhist monument built in Wat Ratchanatdaram in the reign of King Rama III or in 1846, it is the first and only metal castle in Thailand. The first and second metal castles in the world were in Savatthi, India, and Anuradhapura in Sri Lanka. Unfortunately, the two had collapsed two thousand years ago. Loha Prasat in Bangkok was modeled after the one in Anuradhapura. The castle was built in three levels with 37 golden spires with Buddha relics enshrined at the apex. Inside there is an exhibition that depicts its history and construction processes. At the top, you can enjoy 360-degree panorama of the Rattanakosin Island. According to its marvelous cultural and architectural significance, Loha Prasat was registered as a National Heritage Monument.