The phenomenon known as the Naga fireballs (bang fai phaya nak) also known as the Mekong lights in which glowing balls are alleged to naturally rise from the water high into the air. The balls are said to be reddish and to have diverse sizes from smaller sparkles up to the size of basketballs; they quickly rise up to a couple of hundred metres before disappearing. The number of fireballs reported varies between tens and thousands per night