This style of housing originates in 16th century Europe and refers to a row of houses, built in an identical style, sharing a side wall. They are often in a row of three or more whereas two attached houses are semi detached and 3 houses become terrace. Mid-terraced housing is commonly associated with Victorian working class housing in formerly industrial areas. However, some of the wealthiest areas in London also have examples of mid-terraced houses such as Belgrave Square and Carlton House Terrace. These are classic examples of Georgian architecture.