Final tile laid at London Olympic 2012 pool

The laying of the final Olympic swimming pool tile has marked 500 days until the start of the Paralympic Games.

British Paralympic swimmer Liz Johnson laid the 180,000th tile at the Aquatics Centre in east London.

About 4,200 Paralympic athletes from 170 countries will compete at next year's games.

The first Paralympics were in Rome in 1960, but the games' origins can be traced to the 1948 London Olympics.

It was then that Dr Ludwig Guttmann, who was working with war veterans with spinal injuries, organised the first Wheelchair Games at Stoke Mandeville Hospital in Buckinghamshire.

Ms Johnson, 26, won gold in the 100m breaststroke in Beijing in 2008 and said she was confident that she was on course to peak in London.

"You can really imagine what the atmosphere will be like in 500 days' time in such a fantastic venue," she said.

"I can't wait to compete at the Aquatics Centre in front of thousands of fans."

London 2012 chairman Lord Coe said that the organisers would like the public to get involved with the Paralympics as much as possible.

"The London 2012 Paralympic Games will be one of the most memorable sporting events people will have the chance to witness here in the UK, with elite athletes competing at the highest level possible," he said.

The centre, which cost £269m, is on track for completion this summer. It will then host some test events in preparation for 2012 Games.