Wat Ratchanadda was built in the reign of King Rama III to bestow his beloved nephew, Prince Somanutwatanawadee. He organized the construction by himself. The temple complex consists of Ubosot, Wihara, public hall and the unique Loha Prasart (metal castle).

          Loha Prasat (metal castle) is one of the distinguished Thai architecture. Loha Prasat locates at the center of the temple. The central spiral stair is a main circulation through seven floors. The 37 Thai traditional style towers imply the 37 topics of the Buddha's teaching.

          According to Buddhist history, Loha Prasat used to be built in India and Sri Lanka and they were ruined, so that Loha Prasat at Wat Ratchanadda is the third one that are still remain in the world.

Merit making	Sacred Budda ash at the top

           In Buddist's tradition, Loha Prasat is a place for the monks to make their ritual ceremonies. Its cascaded roofs always made of metal. This Loha Prasat has never been complete in construction until the present reign, the Fine Art department and the Civil Works Department both renovated and finished in 2002.

          There are just two remaining evident Loha Prasat in the world. The first one was in India. It was built in the period of the Lord Buddha, with a huge construction in two storiey building with 1,000 rooms and golden roofs.

          The second one was built in AD 1325 at Anuratpur in Sri Lanka. The building size was a square plan of 50 metres in width and length and 50 metres hight. Its nine storeyed building contained 1,000 rooms. The outside wall was adorned of ivory and jewelry. The roof was copper sheet. It was burned and rebuilt a seven storeyed building instead. Now, just the columns remain.