Obri dul Valley
Obri dul is a perfectly developed mountain valley, together with Labsky dul the only two glaciated valleys in the Czech Republic. It is situated between Pec pod Snezkou and the foot of Snezka Mountain, and is bordered by the Siroky hrbet ridge and Studnicni Mountain.
From the 16th century until the beginning of the 20th century copper, iron and arsenic ores were mined here. Three moraines have been preserved in the valley, cut across by the River Upa, by corries (namely Upska jama, Velka Studnicni jama and Mala Studnicni jama), gorges, waterfalls, avalanche slopes and meadow enclaves.
Rare species of mountain flora and fauna occur here, with the area called “Krakonosova zahradka” (Krakonos’s garden) being of special biological value. In summer, Snezka can be ascended through Obri dul. In winter the valley is closed due to avalanche threat.