Burj Khalifa opened on this day three years ago. I have not yet stepped inside or been to the observation deck. I've never felt the need to go inside, I'm happy to it from a distance.
But here's a clip that gives you a closer look at the building. BBC's Supersized Earth recently featured a segment about Burj Khalifa and how the world's highest windows get cleaned. It takes three months to clean all 24,000 windows.
I had a knot in my stomach watching this video. Hats off to the brave men who do this job everyday.