Saint-Pierre by Le Corbusier
Saint-Pierre was designed by Le Corbusier before his death in 1965. Construction began in 1971 however stalled due to political & funding issues and was then completed in 2006 by Corb’s student Jose Oubrerie. Located in Firminy, France the original purpose of the building was a church but it is now used as a cultural venue. It’s very high on my list of buildings to visit.