Barracuda Lake, situated on the north shore of Coron Island in the Philippines, offers one of the most unique diving experiences in the world. Occasionally referred to as Luluyuan Lake by locals, its crystal blue waters hidden between majestic rocky formations aren’t big on actual barracudas and other wildlife. Instead, divers can experience a thermocline and halocline unlike anywhere else.

Starting out on the surface of the lake, divers, swimmers, and scuba enthusiasts can expect temperatures around 82 degrees Fahrenheit. But as you descend into the depths of the lake, around 45 to 50 feet down, the temperature drastically changes to just over 100 degrees Fahrenheit (to put that in perspective, most people keep their hot tubs at 104 degrees, so it’s best to forego a wetsuit here). 

This strange increase in temperature is due to the fact that the lake contains both salt and freshwater. Divers can even see the thin, distinct boundary that separates the two bodies of water. The lake is also characterized by an impressive display of limestone formations that rise up on all sides and extend beneath the surface. 

Divers have described a sense of “weightlessness” while exploring the hot/cool depths, and the sensorial experience (which is largely devoid of flora and fauna) has also been likened to what it must feel like to walk on the moon. But the lake holds yet another surprise: just when the salt watery heat becomes a tad unbearable, the temperature changes back to cool again near the bottom.

Another unique feature of the lake is the sand at the very bottom, which has been described as “jelly-like,” “silky,” “airy,” and “silty.” It’s apparently good for play, too. And although the barracudas aren’t really around anymore, if you’re lucky, you may still catch a glimpse of one.