While traveling in Thailand or Laos, you may very well have come across the famous photo of a large group of American soldiers holding up what is supposed to be a dead specimen of a giant snake. Rumor has it the picture is a hoax; to locals, it is photographic evidence of the Naga, a giant and magical serpent they believe lives in the Mekong River to this day. Most foreigners scoff at this local superstition, but something very interesting occurs in October that should tickle the adventurous side of even the most jaded traveler.

The fireballs of Naga…one of the world’s remaining unexplained mysteries.

In the beginning of October, just as Buddhist Lent comes to a finish, locals gather in the thousands to watch mysterious balls of fire or light come out of the great Mekong River and take to the sky, disappearing high in the air. The size of tennis balls, these lights occur at various points of the river, sometimes in the hundreds or even thousands—sometimes there are only a few though, and in other years there are none at all.

Locals believe these “fireballs” are the work of Naga and say the phenomenon has been occurring for centuries.

Of course, science has tried its hand at debunking the Naga fireballs with a natural explanation, but so far they have failed. Some theorize the balls are formed by gases that build up in the sediment of the river and that Buddhist lent coincides with this region being closer to the sun.

The theory is that a stronger gravitational pull causes the gas to rise and combust as it reaches the surface of the river.

This idea is not without its holes; actually, many have had a field day tearing it to pieces. Some critics point out that these theoretical pockets of gas could not withstand the mighty currents of the Mekong. Not to mention that the Mekong riverbed has proven to be free of the sediment needed for such a scenario.

Other attempts to explain the mystery have raised huge controversies and an outcry from a public who feels they are considered simple country folk who don’t have a clue. One TV program raised a big fuss in 2002 when they claimed to have debunked the myth. A video released to the public showed Laos soldiers on the other side of the river shooting tracer bullets into the air as the Thais on the other side oohed and ahhed.

The story hardly explains the phenomenon, however, as the fireballs occur all over the Mekong, often in desolate places where people are very unlikely to be. A hoax of out-of-this-world proportions would be required in order to make the lights appear even in places where they are so unlikely to be spotted.

Not to mention the Laos soldier “explanation” dismisses the crowds of viewers who gather on the Laos side of the river, where some say the most beautiful displays are said to occur.

Whatever the truth to the fireballs of Naga, it’s always nice to be reminded there are things in the world our scientists can’t put their finger on.

If you want to see it yourself, head to Nong Khai in Thailand around the 12th of October. With actual road signs promoting this magical event, it won’t be hard to find, and even if the lights don’t show up, there is a huge party on both sides of the river, with boat races and all kinds of other festivities.

Because there has been less publicity in Laos (and zero promotion to tourists, it seems), foreigners will have to put some real effort into finding the party. But that also means less crowds and you are likely to be the only foreigner present, which always makes for a unique experience.

Rent a motorbike in Vientiane and follow Highway 13 South towards Baan Na, leaving the boat race festival behind you in the capital city, and you can try to join the locals in the fray. Villagers and wealthier families from the capital set up blankets picnic-style on the banks of the river, and vendors come as well, selling the usual Beer Laos and barbecued meats.

I think you’ll find that even if the lights don’t reveal themselves, the chase is still well worth it…