The Barton Creek Greenbelt is just west of Austin, TX.  Begin the out and back at the 0 mile marker just south of the Barton Springs parking lot. Then follow the main trail route out to the Hill of Life. Touch the gate at the top of the Hill of Life and make your way back to the 0 mile marker.  About 24km.  The route has a Strava Segment.

Submitted by Ron Winsett:

Ridge traverse Including Agassiz, Spread Eagle, Lamotte, A-1, Kletting, and Hayden Peak as a loop, starting and ending at Hayden Pass.

Why?  I have been hiking those mountains for over 10 years linking them up, finding the way to make it a loop.  I completed the loop six years ago in a 2 day stretch, and swore I would never do it again.

Campogrosso - Monteviale / Italy
Ortogonale 1 is the military name for a WW1 supply route in the northeast of Italy on the Austrian front.
It’s a system of trails, fire roads and mule track that connects the lower alpine zone of Campogrosso to the plain of Vicenza. The intended use was to guarantee safe passage of troops and military supplies from the plain base to the front.
After almost a century, Ortogonale 1 is a permanent route of almost 50k and is accessible by mountain/gravel bike and by feet all year long.

Beartooth Mountain Range, Absaroka-Beartooth Wilderness outside of Red Lodge, Montana

West Fork Trail #1 to Lake Fork Trail #2 (or reverse). Parking lot to parking lot. Just under 20 miles with over 3,000 feet of elevation gain.

 Summerland Trail, Wonderland Trail, Cowlitz Divide Trail, Eastside Trail, Owyhigh Lakes Trail, Sunrise Park Road, back to junction with Summerland Trail. 55km.