The oldest Eastern Catholic church in Chicagoland, St. Mary Byzantine Catholic church, 2011 Clark St., will celebrate the 100th anniversary of the laying of its cornerstone. While the parish was founded nearly 120 years ago, the current church building has stood since 1918. The celebration will begin with Vespers for the patronal feast of the Dormition, Aug. 14, 6 p.m., celebrated by Bishop John Kudrick, retired bishop of Parma, and assisted by local clergy, followed by a free ice cream social for the whole community on the front lawn. Info: (219) 659-0277.