Tallest buildings...

In Singapore, there are 3 buildings with the same height: OUB centre, UOB Plaza 1 and Republic Plaza, all standing at a height of 280 m (919 ft).
Take Note: The building that held the Vertical Marathon is Swisshotel, standing at 226 m (741 ft). So, the tallest building is not the building that held the Vertical Marathon

The tallest building is the Burj Dubai, in Dubai. It has not been ready for opening so it is not yet considered as the tallest building yet. As of now, the tallest building in the World now, is Taipei 101.

Republic Plaza:

OUB Centre:

UOB Plaza:

Swiss Hotel:

Burj Dubai:

Taipei 101: