St Mark's is small but unmistakable: a 13th-century parish church on the highest square of the Upper Town, with a steeply pitched roof of glazed tiles laid out as two heraldic coats of arms — the older arms of the Triune Kingdom (Croatia, Slavonia, and Dalmatia) on the left, the modern arms of the City of Zagreb on the right. The roof, added in 1880, has become the city's most-photographed image after the cathedral spires.
Inside, the church is more austere than the exterior promises, with works by the early 20th-century sculptor Ivan Meštrović — including a crucifix and a Madonna and Child — and frescoes by Jozo Kljaković. The square in front, with the Croatian Parliament on one side and the Banski Dvori (the Government building) on the other, is the political heart of the country.