The only major parts of the cathedral built later were the Cloisters, Chapter House, tower and spire (1320), which at 404 feet (123 metres) dominates the skyline. Whilst the spire is the cathedral's most impressive feature, it has also proved to be troublesome. Together with the tower, it added 6,397 tons (6,500 tonnes) to the weight of the building. Without the later addition of buttresses, bracing arches and iron ties, it would have fallen down, as spires on other great buildings have done. Instead, Salisbury is said to be the tallest surviving pre-1400 spire in the world. To this day the large supporting pillars at the corners of the spire are bent inwards under the stress.