Grand Palace (open at 8:30 AM, enter right away) → Wat Phra Kaew (Temple of the Emerald Buddha) → Wat Pho (birthplace of Thai massage) → Take a Chao Phraya River express boat to Wat Arun for sunset → Asiatique Riverfront Night Market.
Early morning Damnoen Saduak Floating Market → Mae Klong Railway Market → Afternoon Siam shopping district (Siam Paragon / CentralWorld) → Chatuchak Weekend Market (only on weekends) → Late-night snacks in Bangkok’s Chinatown on Yaowarat Road.
Erawan Shrine → Erawan / Central Embassy / ICONSIAM → Thai massage (at Health Land or Let's Relax) → Sky Bar or rooftop views at Lebua State Tower (The Dome).
Sanctuary of Truth (Erawan Museum) or Ancient City (Muang Boran, the 72 Provinces) → Return to the airport in the afternoon. If time allows, consider a one-day trip to Ayutthaya (historical sites + train experience).