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El Caminito del Rey, Malaga, Spain
You'll have to wait a few years to tackle this walk—after two fatal accidents, El Caminito del Rey is officially closed to tourists. However, the area is now being restored and is set to reopen to the public in 2015. The cliff-side pathway was originally constructed in order to allow workers to cross between the hydroelectric power plants at Chorro and Gaitanejo Falls, but its dangerous beauty soon attracted hikers and adventure seekers. The 3.3-foot-wide walkway was built into the cliff face 330 feet above El Chorro river, and visitors had to navigate without handrails and over crumbled sections. Once the renovations are complete, walkers will have protective barriers, lighting, and rails to make the walkway safer.