Marina Velky vir on Orlik, Stredocesky kraj, Bohemia(CZ), 2015

Velky vir is one of a number of marinas and beaches on the Orlik reservoir, which in addition to being a reservoir and a hydroelectric plant, is also an artificial lake for outdoor recreation. It was constructed between 1954 and 1961, is 68 kilometres (42 miles long), and was formed by damming the River Vltava just upriver from Solenice. The hydroelectric plant has a full capacity of 364 megawatts, according to Wikipedia. Unfortunately, I haven't been able to figure out where this beach was. It is fairly close to Zamek Orlik, one of the castles around the reservior that survived the construction.