You don't need special glasses to view the 3D street art in the gallery below, but you do need to approach it from just the right vantage point to see or photograph the full effect.
The mind-bending images are inspired by anamorphism, a centuries-old technique used in frescoes and other drawings to create the illusion of height and width (as such, 3D street painting is sometimes called anamorphic or illusionistic).
Scroll through the pictures to view vivid imagery that turns 2D asphalt into amazing 3D art. Sadly, you won't be able to step up to these ephemeral works in person--most have long since been washed away by the rain.
(Thanks to SmashingApps.com for opening our eyes to some of the top 3D street artists around.)