The remains of the oldest Czech dam can be found about 1 km east of the village Strážný about 25 km south of the town Vimperk near the Czech-German border.

It was probably built in the 14th century on the Řasnice river, a tributary of the Vltava river. At the time of construction it was phenomenal work: the dam was more than 500 m long (51 m at the foot) and 15 m wide at the crest and 15 m high. However water broke through in 1587.
The remains are the important medieval constructional sight.

The remains can be found on the green marked path in the place, where the trail crosses the Řasnice river. It is about 1 km far from the road between Strážný and Vimperk (turning-off right 1 km behind Strážný).