The 21C Museum Hotel was once a bank and the tallest building in Durham. When money and jobs were leaving Durham during the 1970s, the bank also moved out, leaving an empty building. It's now an amazing hotel and art museum. Even with the changes, the history is vividly preserved. When you enter the hotel, start by finding the vault room downstairs. It's made of thick slabs of metal. The hotel decorated the floor with "money" to complete the look. There's also a corridor behind the vault with angled mirrors so security guards could keep watch on all sides. Today you can walk through it yourself. It's a narrow chamber so don't get stuck!
Make sure you see the amazing bathrooms on the mezzanine level. At first glance the bathroom walls are see-through, but once you learn the secret, you will be well out of the public view while doing your business.