Ilača is the most important Catholic pilgrimage site in the historical region of Syrmia. The Marian Ilača apparitions were reported in 1865, seven years after the famous Lourdes apparitions. Shepard from Ilača Petar Lazin claimed that he saw a water on the middle of the field road although there was no rain, and that once he made a whole the water source started there that haven't stop since that time. At the same night, another villager, young Đuka Ambrušević saw a Virgin Mary with a child in his dream and she told him that it is her water spring, that he need to build a small wall around it so that stock don't drink from it. When he woke up he saw the image from his dream next to his bed. Initially church authorities tried to prevent congregation from pilgrimage. Later it was permitted by progressive bishop Josip Juraj Strossmayer. In 1866 small chapel was built next to the spring, and in 1870 construction of a church started. Ilača became target of pilgrimage for Roman Catholic Croats, Germans, Hungarians as well as for Eastern-rite Catholic Pannonian Rusyns. During the Croatian War of Independence church was destroyed by tanks of Yugoslav People's Army active in the area of self-proclaimed Serbian Autonomous Oblast of SAO Eastern Slavonia, Baranja and Western Syrmia. Once the UNTAES finished its peace mission in the Eastern Slavonia, Baranja and Western Syrmia in 1998 pilgrimage started once again to take place.