This took my breath away. The installation is a collaboration between Transsolar climate enginners and Tetsuo Kondo Architects. It was shown at the Venice Biennale. Cloudscape creates a cloud in the interior of the Arsenale. Visitors can walk below, through, and above the cloud on a walkway that could easily be mistaken for a section.

Source:
Transsolar climate enginners
Tetsuo Kondo Architects