Who is Harry Gallagher aka Nightscape and what happened at the One Canada Square Canary Wharf skyscraper?
Urban explorer from East London used to be scared of kids' roundabouts but now performs death-defying stunts on skyscrapers
DIZZYING video footage of two teenagers climbing to the top of the 771ft Canary Wharf skyscraper has gone viral.
It was the latest and most spectacular stunt by YouTube and Instagram star Harry Gallagher, who goes by the name Nightscape.
Here's what we know about the East London daredevil.
Who is Nightscape?
Nightscape is the online name of Harry Gallagher, 19, an "urban explorer" from Barkingside in East London.
He has more than 74,000 followers on and half a million on where he posts photos and videos of his exploits including climbing cranes and tall buildings.
Harry has been free-running since the age of 11 after his older brother was also involved in the sport.
But he was not always such a thrillseeker, his mother Amanda has revealed.
She told: “When he was younger, he wouldn’t even go on a roundabout. At Legoland you couldn’t get him near a fairground ride.”
She added: "His brother was the free-runner in the family but he gave it up because decided he didn’t want to kill himself.
"Harry never had that fear. He just has this passion for it. He is fearless."
What does Harry Gallagher do?
Urban exploring is his full-time occupation, and he also has a merchandise business selling Nightscape branded hoodies, t-shirts and posters.
Last year he collaborated with controversial YouTube star Louis Cole as they climbed a skyscraper in the City of London.
His big break online came last October after he and two friends sneaked into West Ham's stadium at the Olympic Park in East London.
They roamed on the pitch and in the terraces, and Harry posed with his feet dangling from the roof.
The video - viewed more than four million times on YouTube - sparked 13 copycat attempts in the following weeks but police said they would not prosecute him.
Has Harry Gallagher ever been caught by the police?
Harry was arrested shortly after the West Ham stunt when he was caught scaling the Sidemen building in Stratford, East London. He was released without charge.
He was also arrested in 2014 climbing on a building site in Vauxhall, South West London.
Urban explorers tread a grey area in the law. Trespass itself is not a crime, except on protected sites such as MoD bases and the railways.
But thrillseekers could be prosecuted if they are suspected of criminal damage, theft or other offences.
What happened at One Canada Square in Canary Wharf?
Harry's latest video shows how easily he and his collaborator known as "HD.XR" - who was also with him at the West Ham stadium - were able to beat security at one of London's best known landmarks.
He said he believed it would be "near impossible" to reach the top of Britain's second highest building.
But after taking a lift from the lobby, they climbed a few flights of stairs as walked through unlocked doors to enter the pyramid on the roof.
The video then shows them clambering on the outside of the steel structure - lit by the flash of an aircraft beacon - and touching the top of the pyramid.
Harry said he was .
He said: “Out of all the buildings we’ve done, it was probably one of the easiest. I couldn’t believe it. Lift, stairs, doors. It was decently easy.”
Police have said they are investigating the footage.
Does Nightscape Harry Gallagher have a death wish?
Gallagher insists he is careful and trusts his body after honing his skills over many years.
He has said in the past: "We go up to enjoy the experience and to take photos.
"As far as hobbies go, it’s just as dangerous as other extreme sports like motor sports, skiing or snowboarding.
"I feel perfectly safe whenever I climb because I’ve been training for a long time.
"I have been free running for seven years and I think that has given me strength and, importantly, balance.
"When I am at the top, I’m constantly making sure my hands have got a tight grip. I don’t move until I know I am secure."
But he added: "I would be lying if I said I don’t think about falling. But if you think you will fall, you will fall. The key is to think positive."
His mum Amanda said she is proud of him even though she cannot watch videos of his death-defying stunts.
She told the Times: "All the years of begging, pleading, trying to make him stop, got me nowhere. It just falls on deaf ears.
"All of us, his friends and family, we all walk around with our hearts in our mouth when it comes to Harry.”
But as his fame grew she began to understand how it could make money from it through merchandising.
She said: “I know he’s not just doing it to get an adrenaline rush. He’s doing it to keep bread on the table and a roof over our head.”
Where is Harry Gallagher now?
He has just returned from Dubai where he was filming new videos, which he has not yet released.
It is believed he went to climb the giant skyscrapers in the Gulf state - a popular draw for daredevil climbers such as Russian model Victoria Odintcova, 23, who posed dangling by one hand from the 1,004ft Cayan Tower last week.
After landing back in the UK he commented on the storm surrounding the Canary WHarf video as some critics called him "reckless".
He tweeted: "Climb a building and you're 'Reckless' climb a mountain and you're a hero."
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