When I drive down Ratchadamnoen Klang Road towards the Democracy Monument, I often noticed this strange structure in the grounds of Wat Ratchanatdaram. It is marked on some tourists maps as simply “The Metal Castle”. It is really a remarkable structure. As the name suggests, it is indeed made of metal. King Rama III ordered construction of Loha Prasat in the early 19th Century in honour of his granddaughter, HRH Princess Somanas Vadhanawadi.