This is Thailand's most revered spot and one of its most visited. King Rama I built this walled city in 1782, when he moved the capital across the river from Thonburi. The palace and adjoining structures only got more opulent as subsequent monarchs added their own touches. The grounds are open to visitors, but none of the buildings are—they're used only for state occasions and royal ceremonies. On rare occasions, rooms in the Chakri Maha Prasat palace—considered the official residence of the king, even though he actually lives at Chitlada Palace in north Bangkok—are sometimes open to visitors. The Dusit Maha Prasat is a classic example of palace architecture, and Amarin Vinichai Hall, the original audience hall, is now used for the presentation of ambassadors' credentials. If the door to the hall is open, you might glimpse the glittering gold throne inside.
Just east of the Grand Palace compound is the City Pillar Shrine, containing the foundation stone (Lak Muang)
from which all distances in Thailand are measured. The stone is believed to be inhabited by a spirit that guards the well-being of Bangkok. Beware the ubiquitous local con men, often dressed in official-looking clothes, who will try to convince you that the palace is closed and that you need to buy tickets from them. It can be hard to tell who's legit, but don't pay attention to anyone until you're practically already in the palace, as this is where the real entrance is. Proper attire (no flip-flops, shorts, or bare shoulders or midriffs) is required, but if you forget, they loan unflattering but more demure shirts and shoes at the entrance.
Sana Chai Rd., Bangkok, 10200, Thailand