This is the moment when legendary American surfer Garrett McNamara conquered possibly the largest wave to have ever been surfed — measuring an estimated 100 ft high off the coast of Nazaré in Portugal in 2013.

Guinness World Records will make an official determination after researching exactly how high the wave was that day, but if the height is confirmed, McNamara will have broken his own record, which he set riding a 78-ft-high wave in late 2011.

Waves like these can be extremely dangerous for even the most experienced surfers. To handle waves of this size and speed, surfers tow in on Jet Skis, instead of paddling in.

Nazare, where McNamara set the 2011 record, has unique geographical conditions that contribute to massive breakers like this. Thanks to a canyon that’s 16,000 feet at its deepest point and gets shallower as it approaches the shoreline, the waves get compressed and reach unbelievable heights before breaking close to shore.

“In Nazaré, Portugal, the ocean is known as a place of death, not of riding waves,” McNamara said at the time.

Check out another amazing ride recently filmed at Nazaré:

HANG TEN: Surfer rides humongous wave off the coast of Portugal. https://t.co/LLRy0kU2Kx pic.twitter.com/YluWtBUPE3

— ABC News (@ABC) January 23, 2018

Other than Nazaré, the biggest waves around the world include Banzai Pipeline, Mavericks, Waimea Bay, Ghost Tree, Punta de Lobos, and Teahupo’o.