They said it was impossible.
An 1800 quadruple cork trick (try saying that after a few gluhweins) involves flipping four times, while the body simultaneously spins through five complete rotations. 
Many said it was completely unachievable.
But Billy Morgan, a British snowboarder hailing from Southampton glided straight into the snowboarding history books by being the first to land the trick in Livigno, Italy recently:
As you might expect, the quad is a little tricky to land. This guy was attempting the much-less-involved straight triple backflip, and look what happened to him: 
Larger and larger jumps have seen riders increasingly pushing for tricks that were once considered impossible. After somebody achieved the triple cork 1620, there commenced a global race to see if the quad – which involves one full flip and half a rotation more than the triple – could ever be done.
And now it has. 26 year-old Morgan, who represented Great Britain at the 2014 Winter Olympics in Sochi, landed the trick on his very first attempt, although he’d been preparing for it for six months. He told The Guardian:
“In the end you just have to go for it, really. You need to know you have got the air time, feel confident, have friends around you and, yeah, pray that you land on your feet”.
Good for him... Now what about the quintuple cork?