Near Gorica pri Slivnici, by the road to Podčetrtek there is lake, Slivniško jezero with an area of 84 hectares, or the Kozjansko Sea as it is jokingly called by many. The lake is 5 km long and half a kilometre wide. It was created in 1976 by damming the Dobrina and Ločnica streams.
The eastern part of the lake, including the outfall of the Dobrina and Ločnica, is a spawning ground for fish. Informally, it has been declared as an ichthyologic and ornithological reserve extending over approximately 40 hectares of water and the surrounding area. It is inhabited by approximately 130 species of birds and 32 species of fish, crayfish, lampreys, frogs and mussels, as well as some rare plant species.
It is a popular fishing destination, with a record catch of catfish, mackerel, carp and zander. The lake is suitable for water sports, and the surroundings for walking, cycling and observing rare fauna and flora.