The Haiku Stairs, Hawaii
Although hiking up the Haiku Stairs (also known as the Stairway to Heaven) is legally restricted, a number of people still make it up the 2,120 foot climb to get to the extraordinary view that awaits them at the top. Initially, the steps were used to allow access to a radio tower at the top, but after it was rendered obsolete, lack of maintenance of the steps made them a hazard.
Although completely repaired, it is still not legal to climb the ascent on them. While that may seem disappointing, the view of the site alone is worth the time to see while on Oahu.