Traverse from Cochamó to Puelo Valley

This traverse is a historic route that connects the Cochamó with the Puelo Valley in Northern Patagonia in Chile.
The traverse is a 73k (45 miles) long trail on a difficult course with 3.449 mts. (11.314 ft.) of elevation gain.
 

Josh Grant describes the route (2WD access version, 50+km as described):

This is Death Valley's premier big loop route with so many reasons why:

1) It's a loop, no car shuttle issues. Titus Canyon is a GREAT run, super scenic, but the car shuttle can be onerous and there's no water until about the end.

David Von Stroh submitted this ~50km route:

Run the Golden Gate Bridge and the Richmond Bridge in one go, starting from Embarcadero BART and finishing at El Cerrito del Norte BART in the clockwise direction (or reverse).

The Gotthard 100k navigates the heart of the Swiss Alps.
This is a fundamental road circuit, usually favored by motorsports enthusiasts and cyclists. However, it is also a perfect road ultra marathon route, that adds up to 100 km distance if start/finish are at the same spot. The route passes by snow-capped mountain peaks, glaciers and goes through three cantons (Uri, Valais, Ticino).