Khao Wang is an historic palace built on a hilltop by King Mongkut, or Rama IV. Known in Thai as Phra Nakhon Khiri, it has an observatory as the king was a devout astronomer. Petchburi’s Khao Wang is probably as famous for its market down by the road, selling Khanom Mo Keang, a Thai sweet made of crushed steamed mung bean, egg, coconut milk and sugar, and Khao Kriap, a dry pastry prepared with coconut, sugar and sesame and then grilled over a charcoal fire. There are also delicious custards and cookies as well as caramelized fruit to delight those with a sweet tooth.