Exploring an abandoned mine with no outside contact. 
Me and a friend didnt tell anyone where we were going. Then tried to climb down the emergency escape ladder system 600ft. We got 200ft and it was falling apart so we decided to go back up. As I got off the entire shaft collapsed in on itself and hundreds of pounds of steel went crashing to the ground in a pile of twisted metal. 
One of the most exciting vacations I ever took