The illusion of a contradictory space within another urban space was arguably instigated by 3D street art. First attributed to artist/architect Kurt Wenner and further popularized by Julian Beever, their chalk paintings use anamorphosis projection to create a 3D illusion when viewed from specific angles (see appended).
The realm of visual effects affords more unique opportunities as seen in the seminal 2005 Sprite commercial, Liquid Freedom. The ad was conceived by John Shaw, Simon Handford & Sylvester Song at the Hong Kong office of agency Ogilvy & Mather. Directed by Josh Taft at Gang Films, the spot features a basketball court that unexpectedly doubles as a swimming pool with visual effects by French firm BUF (famed for their digital set work in Fight Club and Panic Room).