The "Septemvriytsi" monument is located in the area of the Lakatnik Rocks and was erected in memory of the participants in the September Uprising of 1923. It is located in a panoramic place with a view towards the Iskar Gorge.

On September 28, 1923, three days after the outbreak of the uprising, Milan Petrov, Stefan Trifonov, Yordan Kurtev and Dimitar Boyadzhiev died on the rocks near Milanovo village. They were shot and thrown into the ravine from Osikovo Stones after the battles in the area.

A monument was erected in memory of the fallen, whose form resembles a soldier's cap. For years their remains were kept in a basement under the monument. In 1950, Osikovo village was renamed Milanovo — after Milan Petrov, a native of the village.

Today the monument is both a historical landmark and part of the tourist routes in the area, combining memory, history and impressive natural views.