Green Karst Trail is a multi-day bikepacking adventure through the wild and beautiful karst landscapes of southwestern Slovenia, created by cyclists for cyclists. Starting and finishing in Postojna, just 1 km from the famous Postojna Cave, riders choose between two self-supported routes: the Green Route (300 km, 5,000 m elevation) on gravel tracks through forests, karst caves, and intermittent lakes, or the longer Red Route (450 km, 7,800 m elevation) which adds the native Karst, Lipizzaner horse country, and the Nanos plateau. It is not a race — it is an endurance challenge with live tracking, GPX navigation, and local hospitality at GKT Friendly Points along the way.