A grass mowing competition
The meadow of Strljanica is in Kupres, and it gives its name to the annual grass mowing competition.
Each year competitors gather - many of them apparently called "Ivan" - to cut the grass in the meadow. It is the men who cut, training from an early age, while women rake the grass and prepare food. The altitude and the fact that the grass has to be scythe-cut means that it is a real test of strength, agility and technique. Here is the page about the festival on the UNESCO site and if you scroll down you can see some of the traditional costumes worn to celebrate this event. This YouTube video explains more about the event and its history.