Kajmakcalan is the highest peak of Mount Nidje in the Republic of Macedonia (2,521 m) and during the First World War it was a key position of the Macedonian Front. The Battle of Kajmakcalan (12-30 September 1916) was remembered in history because of the great number of victims suffered by the two warring parties, that is, the Bulgarian and Serbian armies. Due to the steep and narrow trails, it is advisable to visit this mountain peak exclusively with an experienced guide. At the very top the church of St. Peter is built, in memory of the killed soldiers from the WWI, and next to the church there is a memorial ossuary. Even today, the shepherds and mountaineers qiute often still find bones of soldiers killed in the battle. From the peak Kajmakcalan, one can see the Lake Ostrovo and Lake Petersko, as well as the ski resort Voras and the Mariovo region in Macedonia.