Naga Fireballs on the Mekong River—known locally as "bung fai paya nak"—are a phenomenon that largely remains unexplained by science. They are part of folklore and legend similar to St. Elmo's fire, the glowing light often reported by mariners from ancient times to the present. The Mekong River Fireballs in Thailand are bubbles of light that burst out of the river waters in an area around Nong Khai, just southeast of Vientiane and near the border with the Mekong River in Laos.
The Naga Fireballs appear regularly on the night of the full moon after the Buddhist Lent, which lasts from July to October. They appear only on this one night, from about 6:00 p.m. to about 9:00 p.m., rise silently for several hundred feet and then disappear. The glowing bubbles, which some say are blown from the mouth of the dragon or sea serpent named Naga and others say are pockets of methane gas bubbling up from river sediment.
These mysterious Mekong River fireballs in Thailand are best viewed from the beautiful riverside Wat Pa Huak Temple built in 1861 or from onboard ships on Mekong River cruises. On the much anticipated night, local boats are decked out in oil and electric lamps for a parade down the river to view the hundreds or thousands of glowing bubbles rise into the sky and disappear. You can also purchase a place on one of these boats.