Hill Valley Zip Line Tours - Unisex SweatshirtDoc Brown's zip line technique involves zero harnesses, one lightning bolt, and a complete disregard for OSHA regulations established decades later. Somehow Hill Valley still gave him a tourism license in 1955. Inspired by Back to the Future. The Details: Cursive golden amber script at the top reads "Hill Valley." A large distressed clock face with Roman numerals sits center, showing a silhouette of Doc Brown dangling from the minute hand, flanked by