On a clear day you can see 80 miles and five states and on an overcast one you are floating in the clouds, detached from the world below.

BBC: At 80, the Empire State Building strikes back

First came an indoor ski resort in 2005, then a floating palace hotel in the sea in 2008, and in 2011, a record-breaking stratospheric tower pierced the clouds.

BBC: Going global in Doha