2012 Paralympics: Huge crowds cheer David Weir to victory
Thousands of spectators have lined the route of the wheelchair marathon through central London to cheer GB's David Weir to a fourth gold medal at the Games.
He said the support from the sun-baked crowd on the final day of the Games had been "amazing the whole way through".
Team-mate Shelly Woods took the silver in the women's race, as GB cemented third place in the medals table.
Coldplay will perform at the closing ceremony from 20:30 BST.
The event will end what has been the most successful event in Paralympic history.
Speaking to BBC Radio 5 live on the final day of London 2012, organising committee chairman Lord Coe said: "It has been fantastic. We wanted to raise the bar at the Olympics and I am as proud as everyone at being a part of a team that has unquestionably raised the bar at the Paralympics.
"We get Paralympics sport in this country. I never really doubted that the Paralympic Games would be anything other than a show-stopper."
The Park was closed at 14:30 BST and people with tickets for the last football and rugby matches were ushered into their respective venues.
Those with closing ceremony tickets will not be allowed into the Park until 17:30 BST.
In a fitting finale to the track and field competition on Saturday, South Africa's Oscar Pistorius - famously known as the "Blade Runner", and one of the faces of the Games - won gold in the the T44 400m.
After the race, the 25-year-old said: "This is one of the most amazing competitions I've ever been a part of, it's been a privilege to be here.
"I think everybody's perceptions of disabled sport has changed."
Channel 4 revealed more than four million people tuned in to watch Pistorius cruise to gold, peaking at 4.2 million during the race.
On Sunday, Brazil's Tito Sena won the T46 marathon, while Alberto Suarez of Spain took the gold in the T12 event, breaking his own world record with a time of 2:24:50.
The crowds then swelled to watch Weir, nicknamed "The Weirwolf of London", add a fourth gold medal to his London 2012 haul.
The 33-year-old's triumph, after 5,000m, 1500m and 800m victories, means he matches Sarah Storey as Britain's most successful athlete at the Games.
After securing four wins out of four, he said: "It's a dream come true.
"I did have lots of dreams of winning four gold medals but I think everybody has those dreams. I knew I was capable of doing it."
Competitors in the men's and women's marathons started and finished in The Mall, completing one short and three long loops during the 26.2-mile race through central London.
One spectator on the route near The Mall said the race was the culmination of six weeks of wonderful sport, and that the Paralympics had "taken it up another notch".
"It's been so good being part of the atmosphere."
Weir and Woods would have both needed to secure gold for ParalympicsGB to overtake Russia for second in the medals table.
But Sunday's result gave the team third spot, with a tally of 120, including 34 golds.
Ceremony sold out
Thrilled at winning the silver medal, Woods said: "I can't describe how great it feels. All the hard work is worth it. A silver in London is just unbelievable."
On Saturday, popular swimmer Ellie Simmonds' loss of her S6 100m freestyle title to USA's Victoria Arlen, despite recording a personal best, saw the 17-year-old finish the Games with a haul of two gold medals, a silver and a bronze.
"I'm quite emotional," she told 5 live on Sunday. "I'm sad it's ending but I'm looking forward to the closing ceremony and looking back at what I've achieved - I'm surprised at what I've achieved."
She added: "I swam the best I could and to come away with personal bests in every event is brilliant."
Once Sunday's sports have concluded, the closing ceremony will bring the curtain down on what has been one of the most successful Paralympics in the event's history.
Organisers have sold some 2.7 million Paralympic tickets - beating targets by 200,000 and predicted sales by £10m.
Sports minister Hugh Robertson said: "The way the British public has taken it to their heart has just been great. I've never known a summer like it."
The UK's papers on Sunday reflected on what the Observer called a sporting "summer in a million".
"Two sporting extravaganzas, a record-breaking medal haul for Britain, disabled sport showcased as never before… no wonder even the Aussies say it was better than Sydney," said the Independent.
The 70,000 Games volunteers were hailed by the Sunday Express, which said: "Unfailingly cheerful, polite and helpful, [they] not only made the Games a success, but restored pride in some good, old-fashioned British values."
Stars due to perform at Sunday's sold-out ceremony include Jay-Z and Rihanna.
The live broadcast of the ceremony is due to start at 20:30 BST and organisers hope it will finish by 23:00 BST.
British stars of the Olympics and Paralympics will then celebrate their success during a victory parade through the streets of London on Monday.