1. Upper 5th Avenue (49th Street to 60th Street)
$3,500 per square foot
Anchored by Saks Fifth Avenue to the south and the Apple Store to the north, this stretch is famous for luxury retailers and their flagships stores. Tiffany & Co., Bergdorf Goodman, Harry Winston, Rolex, Louis Vuitton, Versace and Gucci line this avenue, making it the most expensive retail street in the U.S. — and the world.