Bun Bang Fai or The Rocket Festival is an ancient local festival, which is associated with Thai traditional beliefs in the supernatural powers that help promote the production of rice crops for the coming planting season. In the rainy season, the local people believe that the god would hear the entreaties that they create a rocket or 'Bang Fai' to send to heaven, and bless them with plentiful rain for rice cultivation.
It is believed that the farther they go, the more rain will fall on the northeastern plateau, bringing good fortune and a bumper rice harvest.
Bun Bang Fai, or the rocket festival, is a merit-making ceremony held throughout the northeastern region and in neighboring Laos Although Bun Bang Fai is held in many villages, the largest celebration occur at Yasothon.
Dating back to pre-Buddhist times the Bun Bang Fai is held around the May full moon, and is based on the notion that launching bamboo rockets skyward will initiate the rainy season and bring much needed water to the country's rice fields. Traditionally, rockets are constructed out of bamboos and stuffed with gunpowder, but today, many different materials are used, including PVC or metal piping. These rockets come in variety of sizes starting from foot-long bottle rockets to an absurd nine meters in length.