Beijing is famous for its ''siheyuans'', a type of residence where a common courtyard is shared by the surrounding buildings. Among the more grand examples are the Prince Gong Mansion and Residence of Soong Ching-ling. These courtyards are usually connected by alleys called ''hutongs''. The ''hutongs'' are generally straight and run east to west so that doorways face north and south for good Feng Shui. They vary in width; some are so narrow only a few pedestrians can pass through at a time. Once ubiquitous in Beijing, ''siheyuans'' and ''hutongs'' are rapidly disappearing, as entire city blocks of ''hutongs'' are replaced by high-rise buildings. Residents of the ''hutongs'' are entitled to live in the new buildings in apartments of at least the same size as their former residences. Many complain, however, that the traditional sense of community and street life of the ''hutongs'' cannot be replaced, and these properties are often government owned.