The Mystery Spot is a roadside attraction in the redwood forest above Santa Cruz where visual illusions make people appear to lean at impossible angles and balls appear to roll uphill. The tour takes you through a small tilted cabin built on a steep slope, where the disorienting effects are strongest. It has been operating since 1939 and has the cheerful, low-tech atmosphere of a mid-century American curiosity.
The illusions are entirely explainable by the tilted environment and human perceptual limitations, but they work well despite this — most people find themselves genuinely confused at least once during the tour. Admission is charged; tours run throughout the day. The drive up through the redwoods is part of the appeal.