Water Festival. The largest annual festival in Phnom Penh, this lively gathering celebrates the reversing of the flow of the Tonlé Sap river. The holiday lasts three days as people flood into the city to enjoy the fireworks, colourful boat races, live concerts, eating and partying. The boat racing dates back to ancient times marking the strengths of the Khmer marine forces during the Khmer Empire.
On November 22, 2010 at least 348 people were crushed to death in a bridge stampede at the festival.