"Lai Heua Fai" Festival, the festival of the fire boat.
This is a festival to ask the nagas (water spirits) to bring good luck.
Each village in many provinces makes and decorates a boat. The boats are then paraded through the town, at night they are lunched onto the river and ceremoniously set on fire as offerings to spirits. This festival involves floating the ritual flowers onto the river, to send of bad luck and give thanks to the water spirits. When holding boat race, people ritually reclaim the land from the Naga, chasing them out from fields and streams and back into the Mekong River.
In Luang Prabang, a big parade happens that day. Most of the village of the town (around 20) are building their own big boat, competing every year for the most beautiful one. Ethnic groups are wearing their traditional clothes, people singing, chanting, dancing, fireworks are launched all around...
This is an event not to be missed if you are visiting in October. The spectacle and parade is only second in grandeur to Lao New Year festivities.