The Rut
It runs every year in Big Sky , Montana ( United States ) in September and consists of four races , a 50 K , a 25 K , a 11 K ( from 2015 , before was 12 K ) and Vertical Kilometer both valid for the Skyrunner World Series . 
<triplet> Big Sky, Montana <subj> United States <obj> country <triplet> Skyrunner World Series <subj> Vertical Kilometer <obj> sport