That's a tough question, something to think aboutHowever, judging by this man's performance earlier this year, I would say North Dakota's tallest building would be a piece of cake ( no offense, North Dakota ). In my mind, this guy is the greatest athlete in the world. Took him 3 hours and 56 minutes to climb the 3,000-foot Freerider route on El Capitan. About 90 minutes later, he stood literally on top, almost on top of the world:So I was just sitting around thinking, how long would it take him to climb North Dakota's tallest building? I'm going to predict less than 15 minutes, but it's safe to say we will probably never know for sure.