I'm sure we all know a few trails that match that description, but if you happen to be looking to add a couple more to your collection, Active Junky has quite a list for you. They've compiled a list of 30 terrifying trails, and have included some amazing pictures to back up their claims.
Some of the trails that have earned a spot on this dubious list include the Narrows on Longs Peak in Colorado, the Half Dome Route in Yosemite, and Rover Run, which gets the nod do to the frequent bear activity that occurs around the route. Unsurprisingly, the via ferattas of Italy also make the cut, as does Aokigahara, Japan with a trail that passes through the "suicide forest."
This is just the tip of the iceberg however, and there are plenty of other weird, wild, and down-right scary trails to learn about from this list/slideshow. If you're looking for some suggestions on where to hike some freaky trails, Active Junky definitely has you covered. Check out the full list, and start planning your treks, by clicking here.