In 1941 he moved to Los Angeles and remarried. A decade later, in 1951, he founded the architectural firm "Victor Gruen Associates", which was soon to become one of the major planning offices of that time. After the war, he designed the first suburban open-air shopping facility called Northland Mall near Detroit in 1954. After the success of the first project, he designed his best-known work for the owners of Dayton Department stores, the Southdale Mall in Edina, Minnesota, the first enclosed shopping mall in the country. Opening in 1956, Southdale was meant as the kernel of a full-fledged community. The mall was commercially successful, but the original design was never fully realized, as the intended apartment buildings, schools, medical facilities, park and lake were not built. Because he invented the modern mall, Malcolm Gladwell, writing in "The New Yorker", suggested that "Victor Gruen may well have been the most influential architect of the twentieth century."