A mansion is a very large house. Owning a mansion is often a status symbol since they are usually extremely expensive. A mansion may contain numerous rooms and the owner may employ a staff to help look after it and its residents.
In addition to being larger than a normal house, a mansion usually has specially designed rooms meant to accommodate leisure activities of a particular kind. Some will have a conservatory or greenhouse built in while others will have an indoor swimming pool or an Arts and crafts room with huge North oriented windows. Others still will have all three and more. The relative importance of these specially designed rooms changes with the times: At the beginning of the 20th century no true mansion would have been built without a large room with reinforced floors meant to support the heavy weight of an impressive personal library, while at the beginning of the 21st century the presence of a big room designed for a home theatre is a must. Most recently, mansions have been built with integrated domotics, sometimes to excess.
A McMansion (1980s-2000s) is a speculatively-built, price-inflated suburban house meant to imitate a mansion. They are usually built from standard plans, with only some cosmetic detailing and a few design changes available to the buyer. In contrast a real mansion is normally built by an architect to the exact needs of the clients. The costly time spent by an experienced architect is a better indicator of the lasting status of a mansion than the number of its rooms, its total size, or its special amenities. The homes and mansions designed by the late Richard Neutra are good examples of designs which have been nearly perfectly tailored to fit a particular customer.
Haunted houses are often abandoned mansions.