Lapland is the largest and northernmost region of Finland. Its borders follow the three rivers Tana, Muonio and Torne. The hills and mountains are made up of crystalline rocks like granite, gneiss, quartzite and amphibolite. Most tourist sites are mines or subterranea. There are several caves, but they are mostly neotectonic caves and quite small. There is also one of the longest karst caves of the country, but it is a river cave and a 3-day hike from the next road.