ISTRIA 100 by UTMB started in 2013 and today it gathers more than 2500 runners from all over the world. In 5 distances — 100 miles, 110k, 69k, 42k and 21k — courses combine every aspect of Istria: difficult and technical terrain, little bit of coasteering, old medieval towns, deep forests, city centres, muddy valleys, streams and brooks, canyons and many beautiful panoramas.