The Mystery Spot is a visual illusion-based tourist attraction near Santa Cruz, California. It opened in 1941. The operators of the small site (which is about 150 feet (46 m) in diameter) claim at that location the laws of physics and gravity do not apply and provide a number of demonstrations in support of these claims, where water seems to flow upwards, people seem to be standing in slanted positions, etc.
The Mystery Spot is a gravity hill, a tilt-induced visual illusion. The illusion experienced by visitors results from the oddly tilted environment as well as standing on a tilted floor. Inside the tilted room of the Mystery Spot, misperceptions of the height and orientation of objects occur.
Even when people are standing outside on a level ground, the slant of the building in the background causes misperceptions as humans judge the height of people using the slant of the roof rather than the true horizon.