Meet Marble Mountain. It's an insanely complicated maze for marbles that, by the way, is still under construction. "Every element is themed (or will be upon completion) to an aspect of my life or to something that I find interesting," wrote creator Ben Tardif on the YouTube video caption for his maze. "Some of the elements include a roller coaster, ski jump, Times Square, Lombard Street, and a skatepark." 

Sources: h/t AV Club