Flying Turns at Knoebels Amusement Resort in Elysburg, Pennsylvania is the world's only wooden "bobsled rollercoaster," which is pretty much exactly what it sounds like: a coaster that cruises through a long, winding half-pipe course, banking along the edges and picking up speed as it pummels its way through twists and turns. Rather than run on a steel or wooden track to guide them, the cars sit on sets of multi-directional wheels that glide over the hardwood surface, meaning they potentially chart a slightly different path every time depending on any number of factors, from the size, weight and movement of the riders to the weather conditions that might cause the wood to expand or contract.
Since it's not on a traditional track, Flying Turns doesn't zip super fast, but it does pick up speed as it gets moving (there are three "lift hills" throughout the course, which pull the cars up before gravity sends them rolling back down again). And what it might lack in quickness, it makes up for in the rush of unexpectedness that comes with simply letting inertia dictate your path.
The 47-foot high coaster is actually inspired by a handful of similar style trackless coasters that were once super popular in the 1930s, but have since disappeared. Don't let its retro style fool you into thinking its somehow any less of an engineering marvel than modern-day coasters built to break records -- Flying Turns took nearly eight years to complete, and came with its own series of challenges to meet safety standards.