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 ICOMOS Burra Charter, "reconstruction" means returning a damaged building to a known earlier state by the introduction of new materials. It is related to the architectural concepts of restoration (repairing existing building fabric) and preservation (the prevention of further decay), wherein the most extensive form of reconstruction is creating a replica of a destroyed building.
More narrowly, such as under the Secretary of Interior's Standards in the United States, "reconstruction" is "the act or process of depicting, by means of new construction, the form, features, and detailing of a non-surviving site, landscape, building, structure, or object for the purpose of replicating its appearance at a specific period of time and in its historic location."
There may be several reasons for the construction of a building or creation of a replica building or structure.
Sometimes, it is the result of destruction of landmark monuments that is experienced as traumatic by inhabitants of the region, such as through war, planning errors and politically motivated destruction, other times, merely the result of natural disaster. Examples include Yongdingmen (former Peking city gate temporarily sacrificed to traffic considerations), St Mark's Campanile in Venice (collapsed in 1902), House of the Blackheads (Riga), Iberian Gate and Chapel and the Cathedral of Christ the Saviour in Moscow (destroyed by order of Joseph Stalin), Dresden Frauenkirche and Semperoper in Dresden (bombed at the end of World War II). A specifically well-known example is the rebuilding of the historic city center of Warsaw after 1945. The Old Town and the Royal Castle had been badly damaged already at the outset of World War II. It was systematically razed to the ground by German troops after the Warsaw Uprising of 1944. The reconstruction of Warsaw's historic center (e.g., St. John's Cathedral, St. Kazimierz Church, Ujazdów Castle) and, e.g., the replica of the Stari Most built in Mostar (Bosnia Herzegovina) have met with official approval by UNESCO.