THE world is in the middle of a skyscraper boom. Last year a record number of tall buildings were completed; and the record for the world’s tallest is being broken more regularly and more spectacularly than ever before, particularly in the Middle East. Man’s skyscraper drive has, in general, been tethered to his economic one. The height of the tallest building completed in each year has tended to go up and down in tandem with the economy. On average since 1885 the yearly height record has gone up by 10 feet (3 metres) each time. Since the 1960s the pace has picked up to 16 feet.

Up to 1990, tallest buildings were almost always built in North America—in America or, generally during the downward periods, Canada. The years before and after the second world war saw a handful of European and South American exceptions in countries such as Russia and Brazil. Since 1990 the baton has passed from North America to China (via other Asian countries such as Malaysia and Taiwan), and to the Middle East. That buildings are getting ever higher may please architectural buffs, but whether it makes financial sense is a different question. In terms of economic return, the ideal height for a building may not have changed much since 1930, when it was estimated (in New York) at 63 stories. Today’s buildings are heading above 170 floors.