The Blue and Red Lakes of Imotski

Imotski sits between two enormous holes in the ground. The Red Lake is a collapsed cave chamber with vertical walls over two hundred metres high, one of the deepest sinkholes in Europe, and there is no way down to the water at all - you look into it from a fenced viewpoint on the rim. The Blue Lake, a few minutes away, is shallower and can be walked into on a switchback path cut around the inside of the crater, past terraces and rock walls. Its water level swings wildly: full and swimmable in spring, and in some years dry enough by late summer that people play football on the bottom.

The landscape

• The Red Lake - a vertical walled sinkhole over two hundred metres deep, seen from the rim viewpoint.
• The Blue Lake - a crater lake reached by a stone switchback path down the inside wall.
• The rim path - a walkable circuit around the Blue Lake with views into the crater from different angles.
• Imotski's fortress - the old walls on the ridge above the Blue Lake, giving the wider view over both.

When to go

April to June is when the Blue Lake is fullest and the surrounding karst is green. Autumn is comfortable and quiet. High summer here is one of the hottest places in the country, with temperatures well above the coast and no shade in the crater. Check the water level before planning a swim, since it changes year to year.

Things to know

The climb back out of the Blue Lake crater is long and steep in full sun, and there is no shade or water on the way. The Red Lake is a single fenced viewpoint and takes ten minutes; some people find it underwhelming for the drive. The Blue Lake can be completely dry in late summer. Facilities at both are minimal.

Nearby

The Imotski karst fields spread inland, and Makarska on the coast is about forty minutes over the mountain.