Sendangsono is a holy place for the Roman Catholic comparable with Lourdes in France. This place was used by Fatren Van Lith to baptize the first local converted to the Catholic faith. During the month of May and October, which are the holy months to worship Saint Mary, Sendangsono is visited by thousands of pilgrims from different places of Indonesia. This religious-site lies at the slope of Menoreh Mountain in Kulon Progo Regency; 40 km of Yogyakarta.

The visitors can find spring water under a Sono tree. To reach the place, one has to walk from the main road along a narrow path for about five km. until the Promasari Church is reached, then another 2-km walk to reach Rosary-held place. Besides praying and praising God the Almighty by worshiping Holy Mary, the pilgrims usually take some water from the spring, which is believed to heal all kinds of illness and purify places from evil spirits.