Spend a powerful morning at the Tuol Sleng Museum, which documents the harrowing history of the Khmer Rouge and the Pol Pot era, offering insight into Cambodia’s painful past. Afterwards, visit Wat Phnom, the city’s iconic hilltop temple. Then board a fast boat along the Mekong River and feel the wind on your face as you embark on a thrilling and scenic journey that marks your entry into neighboring Vietnam.