Urban renewal is a program of land redevelopment in areas of moderate to high density urban land use. Renewal has had both successes and failures. Its modern incarnation began in the late 19th century in developed nations and experienced an intense phase in the late 1940s – under the rubric of reconstruction

Reconstruction (architecture)

Reconstruction is a term in architectural conservation whose precise meaning varies, depending on the context in which they are used.More broadly, such as under the Burra Charter of Australia, "reconstruction" means returning a damaged building to a known earlier state by the introduction of new...

. The process has had a major impact on many urban landscapes, and has played an important role in the history and demographics of cities around the world.

Urban renewal may involve relocation of businesses, the demolition of structures, the relocation of people, and the use of eminent domain

Eminent domain

Eminent domain , compulsory purchase , resumption/compulsory acquisition , or expropriation is an action of the state to seize a citizen's private property, expropriate property, or seize a citizen's rights in property with due monetary compensation, but without the owner's consent...

 (government purchase of property for public use) as a legal instrument to take private property for city-initiated development projects.

In some cases, renewal may result in urban sprawl

Urban sprawl

Urban sprawl, also known as suburban sprawl, is a multifaceted concept, which includes the spreading outwards of a city and its suburbs to its outskirts to low-density and auto-dependent development on rural land, high segregation of uses Urban sprawl, also known as suburban sprawl, is a...

 and less congestion when areas of cities receive freeways and expressways.

Urban renewal has been seen by proponents as an economic engine and a reform mechanism, and by critics as a mechanism for control.