A classic and majestic trekking route in the Cordillera Blanca (White Range) of the Andes in the region of Ancash, Peru. It is a well established route typically backpacked over 3 or 4 days. It is a one way route, that goes through glacial valleys, along vibrant lagunas, and climbs high into mountain passes reaching up above 15,500 feet in elevation.
The route can be done in a day, as I have, if conditions permit. The information on trail running it is very limited online. There was a race hosted by Sierra Andina years ago that went from the East to West, which is a decent. The West to East route is an overall ascent. Locals are known to make the route with their animals over 10+ hours.
Here is a link that describes it well in detail:
https://www.novo-monde.com/en/santa-cruz-trek-cordillera-blanca-peru/
