The challenge here is to run every trail in the Shaupeneak Ridge Cooperative Recreation Area, starting and ending at the same spot.  Including the short out & back to the waterfall.  About 11 miles with 2000' elevation gain.

Trail map:  http://www.scenichudson.org/wp-content/uploads/legacy/shaupeneak-2016_webmap.jpg

-submitted by Max Gruner

The GR10 is roughly 822km and runs the entire length of the Pyrenees on the French side of the border (in contrast to the GR11, which runs the entire length of the Pyrenees on the Spanish side of the border). There are a couple of places where there are variations on the route, so French runners have designated the GPX tracks on this page as "official" tracks:  http://www.gr10.fr/archives/2018/09/27/37291520.html

Ohio's longest singletrack open to bikes, this trail is in Mohican State Park, located just outside Loudonville OH off Route 3. From the trailhead parking lot it's approximately 25 miles total, with all but about a mile of riding being sweet flowing singletrack.  Runners should go clockwise and mountain bikers counterclockwise, and runners should yield. These trails are part of the Mohican 100.

https://www.mtbproject.com/trail/960984/mohican-mountain-bike-trail-imba-epic