The west bank of the Chao Phraya, once Thailand's capital for 15 years — old wooden houses, canals, and a slower pace.
Thonburi was Thailand's capital from 1767–1782 under King Taksin before Rama I moved the capital across the river to what is now the Old City.
More traditional, less commercial than the east bank — old wooden canal-side houses still stand, orchards survive, monks are more visible in community life.
Wat Arun (technically in Thonburi), Royal Barge Museum, Klong Lat Mayom Floating Market, Bangkok Noi Canal, traditional Thai house museums.
Cross the Chao Phraya by ferry (3–5 THB from multiple piers) or by BTS extension to Krung Thon Buri and Wongwian Yai.