It may not be the most famous lake in Europe nor is it the biggest, but it is certainly the oldest.
And Lake Ohrid, in the former Yugoslav republic of Macedonia, is in trouble. Mediterranean style-resorts and man-made sandy beaches are putting a strain on the lake, say scientists.
Known as Europe's Galapagos, Lake Ohrid is a Unesco World Heritage Site since 1979, and home to 350 species found nowhere else in the world.
The area around the lake is home to several rare and endangered species like the Dalmatian pelican.
The lake, which has a maximum depth of 288m and covers an area of 358 sq km, is believed to have been created more than 2 million years ago.
Its fragile eco-system has been protected from human impact by the Studenchishta marsh, which cleans raw sewage and pollution from water flowing into the lake from the city of Ohrid.
But Ohrid's mayor, Mr Nikola Bakraceski, has announced plans to drain the 75ha marsh and build luxury housing complete with a marina, according to the British daily The Independent.
The proposals also include the replacement of nearby reed beds with beaches made from imported sand, the report added.