MEXICO
For those who wish to stay above ground there is an innovative method for creating fantastic organic Art Noveau-inspired shapes using light-weight concrete:

Bill and Patti’s Art Noveau house

Tim’s house (terrace)

Tim’s house (kitchen)
Pictures from: Flying Concrete
(where you’ll find more inspiring pictures and info)
Now, that’s what I call an improvement of the use of concrete! Viva la Mexico! for breaking out of the concrete box and away from the depressing greyness of regular concrete.