Another architectural movement of recent times, post-modernism is probably the best-known and most controversial one today. Having begun in the United States in the 1950’s, proponents of the movement share no style or architectural theories. The only common thread is their firm rejection of the International Style that dominated through the first half of this century. Many post-modernists have revived older styles ignored by earlier modern architects. One of the foremost American post-modern designers, Robert Venturi, has often borrowed styles from the exteriors of buildings. Other post-modernists have added arches, columns and domes into their designs. This interest in historical styles coincides with a general concern for preserving old buildings. Post-modern architects approve of government efforts to grant landmark status to buildings having lasting architectural value. This action assures that these buildings will not be destroyed or radically altered, which probably is what post-modernists hope for their own creations.