The Krkonoše National Park (Giant Mountains) is the oldest national park in the Czech Republic, established in 1963, and it straddles the border with Poland where the park continues as Karkonoski Park Narodowy. Špindlerův Mlýn sits in the heart of it, which means that step off the ski run or hiking path and you are in protected wilderness.
The park covers alpine meadows, peat bogs, glacially carved valleys, and one of the largest subalpine plateau ecosystems in Central Europe. It is home to rare species including the Sudeten vole, the mountain hare, and in the upper reaches, the rare eagle owl. The high plateau — tundra-like in character — supports plants that are otherwise found only in the Arctic, and the peat bogs at Úpské rašeliniště near Špindlerův Mlýn are among the most intact in the region.
Summer is excellent for hiking and cycling on the well-marked trail network. The marked routes are graded by colour and difficulty, and a trail map from the park information centre in town is essential for anything beyond the resort tracks.