Cool!

Two of the giant air vents at the 'Cheese Grater' - one of London's new City landmarks. Designed by Richard Rogers, it is 224 m high - which will be 47 floors. The name comes from the shape of the building, and the building's shape comes from a planning demand that the building must not block views of St Paul's cathedral.

These giant vents around the foot of the building are coded blue for cold air in, and red for hot air out. Simple!