Ever heard of a cross sea? Sometimes, when the wind hits the right waves, the ocean goes crisscross.
It's called a cross sea, and it's a mesmerizing, otherworldly sight.
It happens when waves from one weather system forge ahead, even though a change in the wind has created other new waves. Sometimes, it doesn't happen right away.
The waves could take place minutes or miles away from the initial weather shift.
The waves run at an angle to each other, creating the gorgeous crisscross pattern.
It's a relatively uncommon yet beautiful sight. One of the most common photos of a cross sea comes from France.
A photographer caught a nearly perfect grid from a fort in the country's Isle de Ré.
Credit: Wikimedia/Michel Griffon
It's more common in shallower waters, like the time someone captured it on a beach in Tel Aviv.
But this natural phenomenon isn't only a thing of beauty. Swimmers and boaters best beware of cross seas. Crisscrossing waves do correct themselves as soon as the older waves start to dissipate.
But in the interim, the unusual patterns can be extremely dangerous for an unsuspecting ship or surfer.
Vessels and people are supposed to hit waves head on. But if they've got waves coming at them from all angles, things can get dicey.
Someone on a surf or boogie board could get thrown straight up into the air if they got caught between two waves, leading to the potential for a dangerous cross landing. The danger to boats both small and large could be similar.