The instructional trail Keltové Na Šumavě (Celts in Šumava) leads in the vicinity of the settlement Popelná about 6 km south-west of the small town Kašperské Hory.

The trail acquaints visitors with the history of Celtic colonization of the Šumava mountains, with the history of the Celtic place Obří Hrad and addresses findings of research works in this place.

The point of departure is in the settlement Popelná near the parking-lot. The path leads up to Obří Vrch (Giants' Hill - 1,005 m) with the Celtic primeval fort and back. It is about 3 km long. From the peak of the hill there are nice views of the valley of the Losenice river and the Kašperské Hory region.
The access to the trail is possible from the road Vimperk - Kašperské Hory, turning left in the village Nicov in the direction of the settlement Popelná (about 3 km). The access is also possible along the red sign from Churáňov mountain (about 5 km), along the yellow sign from the small town Stachy (about 9 km) or along the red sign from Kašperské Hory (about 8 km).

Interesting places on the trail:
Popelná - the point of departure of the trail
Obří Hrad (Giants' Castle) - remainders of the Celtic primeval fort
Losenice river - the valley of the mountain river