The famed Pororoca tidal bore on Brazil's Amazon River is no easy beast to tame.
When the tide hits the confluence of the Amazon and the Atlantic Ocean just right, it results in waves up to 4 m (13 ft) high that can travel for hundreds of kilometers.
This tidal bore has earned a reputation as a surfing hotspot, drawing some of the world's best to ride the Pororoca for some length.
But anybody can ride waves downstream.
Robby Naish prefers going against the grain.
"Five hour flight to LA, 11 hour flight to Sao Paolo, 3 hour flight to Sao Luis, then a three hour drive to a river 80 kilometers inland from the Atlantic coast to SUP a Pororoca tidal bore wave!Only one wave per day for three days, but the longest rides I have ever had."
The famed water sports athlete, with the backing of Red Bull, recently broke the record for the widest ride of a river bore on a stand-up paddleboard (SUP).
Cutting across the daunting tide, Naish paddled 450 meters (1,476 ft 4 in) over the Arari Pororoca, crossing from bank to bank.
Naish has enjoyed a long and storied career on the water.
A 24-time world windsurfing champion -- winning his first world title at age 13 in 1976 -- Naish has also branched out to kitesurfing and now SUP since retiring from competition.
Due to its tidal dependency, the bore appeared at a different hour each day, with Naish beginning his daily preparations at 6 a.m. across three days of attempts.
“The main challenge with the width record was trying to get from one side to the other as the bore tide wave shifts, because it is never connected all the way across at once," Naish said afterward.
"You weren’t just standing there riding one peak for ages. You had to look at the contour of the side of the river and figure out what to do to follow the wave."
Naish completed his 450-m crossing in just under 10 minutes.
He caught his record-breaking wave at 8:38 a.m.
Many times an unofficial world record holder for high speeds and other categories in his windsurfing days, this successful attempt marks Naish's first fully authenticated Guinness World Records achievement.
"This was the first time anyone has organized an actual challenge and record that we were trying to achieve," Naish said. "It was neat and exciting, sort of opens the door for opportunities to think about more things that could be attacked from that perspective."
And, if you ask the 51-year-old, he isn't done breaking records yet.
Whether or not they have anything to do with board sports is a different story.
"There are definitely possibilities out there with all the things that I do, so I’m going to have a look," Naish concluded.
"I’m definitely going to pull the Guinness World Records book out again and look at what the options are. Grow a big beard or something."
"But I see myself as a 'board' person. It doesn't matter if it's surfing, windsurfing, kitesurfing, stand-up paddle, skate, or snowboard. I love the feeling of gliding, whether on water or some other surface."
Having competed around the globe in his career, Naish received a unique challenge on the Amazon, as the combination of river movements, heat, and the particularities of the massive ecosystem made the attempt a tall task.
The fickleness of the bore itself played a major role, for instance.