'Every wall is a door'

That saying is from Ralph Waldo Emerson. Choi Jeong-Hwa took it to heart. The South Korean artist and designer used 1,000 old doors to create a unique 10-story building in Seoul. The public art installation, called "Doors," is said to hold the record for the most doors in a single building. But be careful which door you choose when navigating inside--one wrong door and you're out and down.