Head south of Vukovarska along Radnička cesta and you come to Zagreb’s industrial zone. But many of us may not realise is that the two interconnected lakes here, known as Savica, form a protected area with a nature reserve. When the Sava riverbank was built to prevent flooding, the lakes’ natural water supply was cut off. A large central heating plant lies by them. An outflow of clean water from the turbines replaced the missing water source, and Savica has become a paradise for more than 150 kinds of birds enjoying an ornithological Florida – the water is, of course, warm! The world’s first industrial nature reserve? The lakes are also carefully stocked with fish. You can buy permits at the club there and idle away summer days of tranquility.