The number four is considered unlucky because four in Chinese sounds like the Chinese word for death. Some hotels in China do not have a fourth floor. A few skyscrapers in Hong Kong have no floors with the number in them. So a tall building with a 100th floor penthouse might only have 81 floors because 4, 14, 24, 34, 40-49, 54, 64, 74, 84 and 94 are all missing.