1. Herbert Hoover's 1932 Cadillac
(Photo : Bonhams)
2. 1939 Lincoln "Sunshine Special"
(Photo : Flickr Creative Commons)
3. Dwight D. Eisenhower's "bubble roof" 1950 Lincoln Cosmopolitan
(Photo : Courtesy of the Henry Ford Museum)
4. John F. Kennedy's 1961 Lincoln limousine
(Photo : Courtesy of the Henry Ford Museum)
5. Ronald Reagan's 1972 Lincoln Continental
(Photo : Courtesy of the Henry Ford Museum)
6. President Obama's armored limo
(Photo : Wikimedia Commons)