Olympic Games rings float down River Thames Giant Olympic rings were launched on to the River Thames on Tuesday to mark 150 days until the start of the London Games. Standing at 11 metres high, the structure travelled on a barge along the river, passing the capital's landmarks. Mayor of London Boris Johnson, who will watch Tower Bridge open to allow the rings to pass underneath, also announced a programme of free cultural events that will take place in the city during the Games. We're creating the biggest festival of outdoor arts ever to be seen in the capital ... Wherever you are, you will feel a part of the 2012 celebrations and experience a summer like no other in one of the most exciting cities on earth," he said. These will include a floating opera inspired by The Owl And The Pussycat to be staged on the city's canals and the creation of the London Pleasure Gardens at Pontoon Dock in east London.