An 18-meter structure will typically have 5–6 floors. The height of a story, on the other hand, varies depending on how each level is built and the height of the ceilings. In general, commercial buildings will have more storeys than residential structures. Buildings are often described as "tall" or "short" based on their height: a tall building is one over 40 meters (130 feet), a short building is under 40 meters (130 feet). However, the number of stories affects this calculation: an 18-meter-high building that has three floors will be 54 meters high. In New York City, most buildings are less than 20 stories high, although several skyscrapers reach heights of nearly 100 m (330 ft). In London, most buildings are between 15 and 25 stories high. The tallest building in Europe is 30 St Mary Axe in Manchester which stands at 150 m (490 ft) - a little over half the height of One World Trade Center in New York City which currently holds this record. In Paris, most buildings are between 20 and 40 years old. The tallest building is La Défense at 491 m (1,634 ft), but it was not finished when it opened in 1975 so it can't hold this record forever. In Tokyo, most buildings are between 10 and 20 stories high.