The Gornjak Monastery, formerly known as Zdrelo, is a 14th-century Serbian Orthodox monastery. It's located in the nearness of today's city of Petrovac na Mlavi Petrovac na Mlavi . It was built in the period from 1376 to 1380. as an endowment of Prince Lazar, who was entrusted to the care of Saint Gregory of Sinai, who was said to perform miracles. Namely, each year on St. George’s Day, from a crack in a rock behind the monastery, the water starts dripping and running to a small trough, from which people collect it with spoons. The water is believed to be the tears of St. Gregory and to heal ocular diseases.