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. One of the best-known perennially incomplete buildings is Antoni Gaudí's basilica Sagrada Família in Barcelona. It has been under construction since 1882 and planned to be complete by 2026, Gaudí's death centenary. Partially constructed buildings There are numerous unfinished buildings that remain partially constructed in countries around the world, some of which can be used in their incomplete state but with others remaining as a mere shell. Some projects are intentionally left with an unfinished appearance, particularly the follies of the late 16th to 18th century. Some buildings are in a cycle of near-perpetual construction, with work lasting for decades or even centuries. Antoni Gaudí's Sagrada Família in Barcelona, Spain, has been under construction for around 120 years, having started in the 1880s. Work was delayed by the Spanish Civil War, during which the original models and parts of the building itself were destroyed. Today, even with portions of the basilica incomplete, it is still the most popular tourist destination in Barcelona with 1.5 million visitors every year. Gaudí spent 40 years of his life overseeing the project and is buried in the crypt. Germany's Cologne Cathedral took even longer to complete; construction started in 1248 and finished in 1880, a total of 632 years. Buildings (and other architectural structures) never completed Buildings that were never completed and remain in that state include: Duomo di Siena (Siena Cathedral), Italy Abbey of the Santissima Trinità, Venosa, Italy San Petronio Basilica, Bologna, Italy Goodwood House, West Sussex, England, UK Klosterneuburg Monastery, Austria Herrenchiemsee, Bavaria, Germany Prora, island of Rügen, Germany Woodchester Mansion, Stroud, Gloucester, England, UK Parliament House, Wellington, New Zealand Bishop Castle, San Isabel National Forest, Colorado, US Boldt Castle, Thousand Islands, New York, US National Monument, Edinburgh, Scotland, UK Ajuda National Palace, Lisbon, Portugal Cuenca Cathedral, Cuenca, Spain Jeddah Tower, Jeddah, Saudi Arabia Plaza Rakyat, Kuala Lumpur, Malaysia Ilot