Skyscraper racers reach Vietnam's Keangnam Hanoi Tower
Runners bidding to complete the world's first skyscraper circuit have reached Vietnam's tallest building.
The 300-strong group ascended 1,912 steps to reach the 72nd floor of the Keangnam Hanoi Landmark Tower, measuring 350m (1,148 feet) high.
The 2012 Vertical World Circuit (VWC) includes some of the world's most iconic skyscraper races, including the Empire State Building Run-Up and the Taipei 101 Run-Up in Taiwan.
The BBC's Peter Dobbie reports.