The biggest security operation in the troubled history of Northern Ireland swung into action on Monday for the start of the G8 summit and US President Barack Obama's speech in Belfast.
Obama, who flew in aboard Air Force One accompanied by his family, then took his Marine One helicopter in a squadron of eight US military choppers carrying his entourage to the centre of Belfast.
He apologetically noted his own massive security footprint.
"As our daughters pointed out as we were driving in, I cause a big fuss wherever I go," he said during a speech to young people.
"Traffic and barricades and police officers, and it's all a big production, a lot of people are involved -- and I'm very, very grateful (to them) for accommodating us."
Streets around the Waterfront Hall where Obama spoke were cordoned off and crowds were kept at a distance by police, as the president swept by in his armoured "Beast" limousine, and a motorcade including an ambulance, SWAT teams and communications vans, as well as a fleet of buses for staff and press.
Roads into and out of the city were closed to facilitate the president's visit.
Obama was not driven to the summit deep in the Northern Ireland countryside, instead catching the presidential helicopter from Belfast to Lough Erne, an exclusive golf resort fringed by lakes 80 miles (130 kilometres) to the south.
British Prime Minister David Cameron, the summit host, arrived on Sunday, and other leaders were flying into Belfast before catching helicopters to Lough Erne.
More than 8,000 police officers have been deployed to the British province for the two days of talks to guard the leaders and stave off anti-capitalist and anti-globalisation protests.
Three surveillance drones will also be employed in the skies over the summit venue.
On the drive from Belfast through the lush Northern Ireland countryside, armoured police Land Rovers could be seen positioned every few miles, manned by heavily armed police.
The security was reminiscent of the darkest days of Northern Ireland, but Cameron has said he chose the location to show off the progress the province has made since it has emerged from three decades of bombings, killings and riots.
"Frankly, ten years ago, 20 years ago, it would have been unthinkable to hold a G8 in Northern Ireland in County Fermanagh," he said last week.
Hundreds of journalists from around the world covering the talks are based at a media centre on the edge of the town of Enniskillen, six miles away from Lough Erne.
At the resort, an imposing security fence has been erected around the venue, a collection of whitewashed cottages fringed by lakes which are patrolled by police boats.
Campaigners launched two longboats flying sails emblazoned with the slogan "End Tax Dodging", a reference to Cameron's aim to make progress on cracking down on tax evasion during the talks.
It was a rare show of protest -- police have admitted that far fewer demonstrators than expected have made their way to the venue.
Organisers of the summit have allowed campaigners to set up camp on a sports field, but late on Sunday there were just four tents.
Police say they are expecting around 2,000 protesters to gather in Enniskillen on Monday, campaigning against capitalism and proposals to drill for natural gas locally using a method known as fracking.
A similar number took part in two rain-drenched protests in Belfast on Saturday, when police had been expecting 10,000.