Namtok Phlio is a small but pretty waterfall about fourteen kilometres southeast of Chantaburi, the centrepiece of a national park dotted with royal monuments. The falls run year-round, drop in three tiers into a clear pool full of sizeable carp (you can buy fish food at the entrance), and are a popular swimming spot at weekends.
King Chulalongkorn visited the falls in 1876 and again in 1881 and was sufficiently charmed by them to build a chedi and a pyramidal stupa in memory of his queen, who had drowned in the Chao Phraya near Bang Pa-In. Both monuments still stand on the path up to the falls. Entry is around 200 baht for foreigners.