The construction of a fifth terminal at London Heathrow, seen as critical to the airport’s continuing position as the busiest in Europe, was the subject of a limited competition in 1989. The winning scheme is based on aprojected capacity of 30 million passengers annually and reflects the success of ‘singlelevel’ airport terminals such as London Stansted, designed by Norman Foster for the British Airports Authority, also the clientat Heathrow.The passenger areas at Terminal 5 are on one level, with plant rooms, baggage handling and other ancillary functions below, though passenger areas extend over two levels at both edges of the building. Theimmense roof is dynamically curved, with great bands of glazing flooding the interior with daylight and leading passengers through the building in a logical progression from arrival point to embarkation.The building is effectively a dramatic progression of spaces, which vary in height according to their function. The structure is strongly expressed, with great structural ‘trees’ supporting the roof. Aircraft load and unload at stands on the core building, as well as at two satellites served by arapid-transit system. Provision is made for an underground and mainline rail link from central London, contained in deep tunnels.Natural ventilation is impractical in view of noise and air pollution from aircraft but the design adopts an energy-efficient strategy using a displacement air-conditioning system developed by Arup and shading by means of canopies and low eaves to reduce solar gain on the long east and west elevations. Heathrow Terminal 5 is likely to be one of the most striking examples of airport architecture at the beginning of the 21stcentury and as significant a work in the RSHP oeuvre as the Centre Pompidou in the 1970s and Lloyd’s of London in the 1980s.The new terminal is due to open at the end of March 2008.