Editing Grande Arche (section)

==Design and construction==
[[File:Grande Arche de La Défense et fontaine.jpg|thumb|left|Grande Arche at night]]
A great national [[Architectural design competition|design competition]] was launched in 1982 as the initiative of French president [[François Mitterrand]]. [[Denmark|Danish]] architect [[Johan Otto von Spreckelsen]] (1929–1987) and Danish engineer [[Erik Reitzel]] (1941–2012) designed the winning entry to be a late-20th-century version of the [[Arc de Triomphe]]: a monument to humanity and [[humanitarian]] ideals rather than military victories. The construction of the monument began in 1985, with most of the work being carried out by [[France|French]] civil engineering company [[Bouygues]]. Spreckelsen resigned in July 1986 and ratified the transfer of all his architectural responsibilities to his associate, French architect [[Paul Andreu]]. Reitzel continued his work until the monument was completed in 1989. The Grande Arche is in the approximate shape of a cube with a width, height, and depth of {{cvt|110|m}}; it has been suggested that the structure looks like a [[hypercube]] (a [[tesseract]]) projected onto the three-dimensional world.<ref>{{cite web|last=Du Sautoy|first=Marcus|title=A 4 Dimensional Cube in Paris|url=http://www.mathsinthecity.com/sites/4-dimensional-cube-paris|work=The Number Mysteries|access-date=17 June 2012|archive-date=14 January 2016|archive-url=https://web.archive.org/web/20160114023543/http://www.mathsinthecity.com/sites/4-dimensional-cube-paris|url-status=dead}}</ref>  It has a [[prestressed concrete]] frame covered with [[glass]] and is covered in Bethel Granite.

''La Grande Arche'' was inaugurated in July 1989, with grand military parades that marked the bicentennial of the [[French Revolution]]. It completed the line of monuments that forms the [[Axe historique]] running through Paris. The Grande Arche is turned at an angle of 6.33° about the vertical axis. The most important reason for this turn was technical: with a [[Paris Métro]] station, an [[Réseau Express Régional|RER]] station, and a motorway all situated directly underneath the ''Arche'', the angle was the only way to accommodate the structure's giant foundations. In addition, from an architectural point of view, the turn emphasises the depth of the monument and is similar to the turn of the [[Louvre]] at the other end of the Axe Historique. In addition, the ''Arche'' is placed so that it forms a secondary axis with the [[List of tallest structures in Paris|two of the highest buildings in Paris at the time]], the [[Eiffel Tower|Tour Eiffel]] and the [[Tour Montparnasse]].

The two sides of the ''Arche'' house government offices. The roof section was closed in 2010 following an accident without injury<ref>[http://www.lemonde.fr/societe/article/2010/08/11/le-toit-de-la-grande-arche-de-la-defense-definitivement-ferme-au-public_1397833_3224.html Lemonde.fr], ''[[Le Monde]]'' (11 August 2010)</ref> and the marble tiles which had begun to peel off were replaced with granite ones. It opened again in 2017 after seven years of renovation work. It features panoramic views of Paris and includes a restaurant and an exhibition area dedicated to photojournalism.<ref>{{Cite web|url=https://www.sortiraparis.com/en/news/in-paris/articles/138676-la-defense-grande-arche-rooftop-an-unobstructed-view-over-paris|title=La Défense Grande Arche rooftop: an unobstructed view over Paris|website=www.sortiraparis.com|accessdate=10 March 2023}}</ref>

The void contains skeletal shafts for panoramic lifts and a [[polytetrafluoroethylene|PTFE]]-and-[[fibreglass]] [[membrane structure|tensile-membrane]] sunshade known as the "Cloud" (''Le nuage'').<ref>{{cite web | url=http://archiexpo.com/prod/hightex/product-58335-524257.html | title=NUAGE LÉGER GRANDE ARCHE - PTFE architectural membrane by Hightex &#124; ArchiExpo }}</ref>

The Danish architect, von Spreckelsen, chose Italian [[Carrara marble]] for the tile cladding of the façade, for the marble's gleaming, milky white exterior.  This caused structural problems, as marble is porous, rainwater got into its pores, and when the temperature froze, the ice in its pores cracked the marble, and tiles began buckling and falling down, luckily without, however, hitting, injuring or killing anyone.  The monument had to be closed for a few years while French engineers (von Spreckelsen had retired from the project before it was completed and was dead by the time of the collapsing tiles) had the marble tiles removed and replaced with granite quarried in Vermont, which has proved durable, at a cost of some €200M.{{Citation needed|date=October 2023}}