This is one of the Eight Prangs (Eight Towers) or Chedi on the East side of the Grand Palace Complex. The Eight Prangs are of different colors and each is dedicated to a certain Buddhist concept. This one is Yellow, indicating The Universal Monarchs (Parama Cakravarti Raja).

The form of a Thai Prang or Chedi (tower) derives from the Khmer prasat, but whereas a prasat is "a residence of a king or a god," a prang has the same function as a Chedi. A Chedi is a kind of Pagoda which has a specific symbolism. The base represents hell, the middle humanity and the top the state of nirvana. When faithful people are performing "vien tien" ceremonies ( walking around the Chedi three times ) they are expressing a wish to be whisked from hell to nirvana by a whirlpool.