The Church of St. Mary of the Sea (second name — the church of St. Osanna) is located in the northern part of Kotor's Old Town, on the Trg od drva square. It was built in 1221 in place of an older structure from the VI century.
The church has preserved frescas from the XIV century, supposedly made by Greek masters. It also houses the remains of St. Osanna — a Catholic monk and the protector of Kotor. One of the facades is decorated by 24 bas-reliefs depicting the life of St. Osanna.