The first tile in the London 2012 Olympics swimming pool complex has been laid by world swimming champion Mark Foster.
Some 180,000 tiles will line the 50m (164 ft) competition pool, plus the training and dive pools.
The ceiling of the 17,500-seat venue is being clad with more than 30,000 pieces of timber.
Mark Foster, 50m freestyle world record holder, said it would be a "fantastic facility".
He said: "The aquatics centre will be buzzing during the games.
"Afterwards [it] will be a fantastic new facility for the Olympic and Paralympic athletes of the future and the local community."
Between them the pools will hold 10 million litres of water.
The two seating stands will weigh in at 1,600 tonnes each.
Olympic Delivery Authority chief executive David Higgins said: "Starting tiling of the pools is another milestone towards completing the Aquatics Centre next summer ready for test events.
"With the covering of the sweeping roof complete and ceiling under way the venue is on track."