On the eastern shore of Popovo Lake (more than 2200 m above sea level in the Pirin Mountain), a megalithic altar with an inverted truncated pyramid shape was discovered. Two chutes led the sacred fluid from here on a lower site marked with two elliptical and one circular digging. The open ceramics date back to the second half of the first millennium BC. At the lower Poljean Lake (at the foot of Polejan peak), there is an imposing stone throne. It is oriented exactly to the west. Around the throne, there are round pits on it on large stone blocks - altars. In front of the stone throne hearths are located, which functioned until the middle of the 19th century. Rams were sacrificed here. The pilgrims came with the belief that, like their fathers and ancestors, they would become "Hadji". A fact that suggests a particularly important cult center that left lasting traces of traditional memory and cult activities.