The Krystina Lake
Since about the middle of the last century, brown coal was mined in the vicinity of Hradek n. N. (Grottau).
Count Clam Callas ran a brown coal mine that mined coal in several shafts (e.g. in the Christian shafts).
An important shaft was the Marie shaft, which was in operation with a few interruptions until 1950.
In 1957, the "Krystina" open-cast mine was established. It was only of local importance and supplied the surrounding heating plants with raw brown coal until 1971.
On April 30, 1972, coal mining in the open-cast mine was stopped and on May 8, 1972, the pumps for water management were also shut down. The remaining hole was flooded. In total, it took about 3 years for the water level to reach its current level.
The lake that was created in this way has a water surface of 12.52 hectares with an average water depth of 20 m. In some places, however, it also reaches a maximum depth of 30 to 35 m.
Today, the lake is a popular tourist destination and is well visited when the weather is nice.