Bangkok's set pieces — the palace, the reclining Buddha, the river — reward an early start, and the city's smaller museums and art spaces are cheap, air-conditioned and far emptier by comparison.
The Grand Palace and Wat Phra Kaeo
The royal compound and the Temple of the Emerald Buddha, open daily 08:30–16:30 with ticket sales closing at 15:30; admission is 500 baht. Shoulders and knees must be covered, and going at opening time is the only way to see it without a crowd.
Wat Pho
The reclining Buddha temple immediately south of the palace, and the home of Thailand's traditional massage school, so you can combine the visit with an hour on a mat. Foreign visitors pay an entrance fee at the gate; it is a ten-minute walk from the Grand Palace, or a short hop from Tha Tien pier.
Jim Thompson House Museum
The teak house and Asian art collection of the American silk trader who vanished in 1967, open daily 10:00–17:00 with the last guided tour at 17:00. Adults 250 baht, ages 10–21 150 baht, under-10s free; tours are compulsory and run in five languages, tickets are sold only at the ticket office, and the museum warns about people selling fake tickets online.
Bangkok Art and Culture Centre
Nine floors of rotating contemporary exhibitions, an art library and small independent shops at 939 Rama I Road, open Tuesday to Sunday 10:00–20:00 and free to enter. It connects by skywalk to BTS National Stadium, which makes it the obvious place to sit out an afternoon downpour.
Chao Phraya Express Boat
The commuter boat network is the cheapest sightseeing in the city: the orange line is a flat 18 baht, the yellow 23 and the red 32, with the green-yellow line charging 16 to 35 baht by distance. Board at Sathorn (Central) pier, which is directly under BTS Saphan Taksin, and get off at Tha Tien or Tha Chang for the old town.