Two giant sinkholes – one red, one blue.

Imotski is a small town on the far side of Biokovo mountain, close to the border with Bosnia and Herzegovina. It is famous for two remarkable karst lakes.

The Red Lake lies in one of the largest sinkholes in the world. Its cliffs, coloured reddish by iron oxides, rise more than 240 m above the water, and the lake itself is around 280 m deep.

The Blue Lake sits right at the edge of town. Its water level changes dramatically: in spring it is a deep turquoise lake, while in very dry summers it can almost disappear – locals have even played football on its bottom. A stone path leads down to the water, a favourite bathing spot.