In 1901, 21-year-old William S. Harley first drew up plans for a small engine that would fit into a bicycle -- and an American classic was born. A must-see for motorcycle aficionados, this video takes viewers on the road as bikers from across the globe head to "hog heaven" -- Milwaukee, the birthplace of Harley-Davidson -- to celebrate Harley's 90th anniversary. With footage of special events and custom rides, what more could you ask for?