AUSTRIAN daredevil Felix Baumgartner became the first human to break the sound barrier in freefall in America early on Monday morning (AEDT).
But the 43-year-old sky-diving expert could not explain to journalists how it felt.
"It is hard to describe because you don't feel it," he told reporters.
After a number of aborted attempts due to unsuitable weather, Mr Baumgartner finally took the plunge from the edge of space as millions of people from around the world watched online in awe.
A giant helium-filled balloon took two hours taking the thrill seeker to the jump altitude - 39km above the Earth.
It is there, in a suit designed to protect him from minus 68-degree temperatures and the possibility of his blood boiling, he leapt into history.
Mr Baumgartner was in free fall for 4min 19 sec, falling just short of the record held by Joe Kittingerm, who was part of the Red Bull Stratos support team for Monday's jump.
He reached a top speed of 1342kmh, or 1.24 times the speed of sound.
At one point during his freefall Mr Baumgartner appeared to spin rapidly, but he quickly re-gained control and moments later opened his parachute as members of the ground crew cheered and viewers around the world heaved a sigh of relief.
"It was an incredible up and down today, just like it's been with the whole project," Mr Baumgartner said.
"First we got off with a beautiful launch and then we had a bit of drama with a power supply issue to my visor. The exit was perfect but then I started spinning slowly.
"I thought I'd just spin a few times and that would be that, but then I started to speed up. It was really brutal at times.
"I thought for a few seconds that I'd lose consciousness. I didn't feel a sonic boom because I was so busy just trying to stabilise myself.
"We'll have to wait and see if we really broke the sound barrier. It was really a lot harder than I thought it was going to be."
Mr Baumgartner is no stranger to performing death-defying stunts.
In 2003 he became the first person to skydive across the English Channel using a specially made carbon fibre wing.
He has also set several BASE jumping records.
But he was adamant his latest feat would probably be his last.
"I think I'm done," he said.
Mr Baumgartner and his team spent five years training and preparing for the mission that was designed to improve scientific understanding of how the body copes with the extreme conditions at the edge of space.
Breaking the sound barrier - 1342.8kmh
Highest manned balloon flight - 39,045m (128,000ft)