Monks at Wat Phra Pathom - At 120 meters this massive brick stupa is the largest in the world. It also claims to being Thailand's oldest Buddhist temple, dating back to the 6th century, although the present structure is mostly the handiwork of King Mongkut and his successors. The stupa is said to house a relic of the Buddha, but you can circumambulate the chedi in the inner courtyard. The temple is officially called Phra Pathommachedi and is located in the town of Nakhon Pathom. The name Phra Pathommachedi means Holy Chedi of the Beginning.