People stumble about the labyrinth, arms outstretched. Even so, they sometimes find themselves smacking headfirst into their own reflection. Shrieking and giggling when they reach someone else they ask, “are you real?”

This maze is contained in a nondescript building on San Francisco’s Pier 39. It’s a disorienting dungeon of columns and mirrors, lit by blacklight and flashing neon and scored by rave music. Once you’ve managed to make it through the purveyors have been known to recommend trying it again, this time backwards.

This trippy scene is standard fare at Magowan’s Infinite Mirror Maze for visitors of all ages, no drugs required (or recommended for that matter). Its founder calls it “one part art, one part science.” The trick is simple–you’ve probably seen it before at a carnival–but the effect is still enchanting.

Update February 2018: It appears the maze is now back open for business, after closing briefly with no explanation.