Wat Traimit or Wat Trimit (วัดไตรมิตรวิทยารามวรวิหาร) is known for its giant Buddha image made from solid gold weigh about 5.5 tons. The gold was hidden under plaster for centuries until rediscovery in 1954.
Wat Traimit Witthayaram Wora Wiharn, a second class royal temple, was built around 1832 AD (2375 BE). It was originally named Wat Sam Chin (Three Chinese Temple) after three Chinese donors who contributed their properties to build the temple. In 1929 AD (2482 BE), the name was changed to Wat Traimit Witthayaram and it became a royal temple in 1956 AD (2499 BE). The principal Buddha image, named Sukhothai Traimit is located within the Wiharn (Hall of Worship). The image belongs to the Sukhothai period and was presumably made during the reign of King Ramkhamhaeng the Great (1277-1317 AD, 1820-1860 BE). It was moved from Wat Mahathat in Sukhothai to Wat Chotinaram (Wat Phrayakrai) during the reign of King Rama III. Then it was moved to Wat Traimit and stored in the pavilion before being moved to the present location in 1955 AD (2498 BE). During this move the image, which was covered in white plaster was dropped, cracking the plaster. The image was then discovered to be of solid gold. The entire covering was then removed and the image restored to its current state. It is thought that the plaster covering was added to hide the true nature of the image from Burmese invaders.
Wikipedia article: http://en.wikipedia.org/wiki/Samphanthawong
http://en.wikipedia.org/wiki/Golden_Buddha_(statue)
Wat Traimit (Golden Buddha) #1 by Flitze50, on Flickr