Exposure, as in trails that have give the opportunity to fall to your death. For those who want to talk about exposing yourself, well, we know who you are...
For a good place to hike if you want the thrill of almost falling to a watery grave, I can recommend Pictured Rocks National Lakeshore in Michigan's Upper Peninsula. The Lakeshore Trail runs for 45 miles from Grand Marais to Munising. The first part of the trail follows the Grand Sable Dunes. From here you get a nice view looking down this 300 foot high pile of sand and gravel. So falling down this wouldn't be fatal. In fact some people run down this for fun. but once down, the only way out is to climb back up, and that very well might kill you. Note convenient hiker in the front-right for scale.
For a good place to hike if you want the thrill of almost falling to a watery grave, I can recommend Pictured Rocks National Lakeshore in Michigan's Upper Peninsula. The Lakeshore Trail runs for 45 miles from Grand Marais to Munising. The first part of the trail follows the Grand Sable Dunes. From here you get a nice view looking down this 300 foot high pile of sand and gravel. So falling down this wouldn't be fatal. In fact some people run down this for fun. but once down, the only way out is to climb back up, and that very well might kill you. Note convenient hiker in the front-right for scale.