An unfinished building is a building (or other architectural structure, as a bridge, a road or a tower) where construction work was abandoned or on-hold at some stage or only exists as a design. It may also refer to buildings that are currently being built, particularly those that have been delayed or at which construction work progresses extremely slowly. Many construction or engineering projects have remained unfinished at various stages of development. The work may be finished as a blueprint or whiteprint and never be realised, or be abandoned during construction.