The Trinity column, built to commemorate the plague epidemics of the 17C and 18C, stands on the main square of the castle district. Admire the beautiful Mathias church and, on one of the corners of the square, the Baroque palace (late 17C), which housed Buda's former town hall. A pinnacle turret with a clock rises above what was formerly a chapel, where a statue of Athena, the town's guardian, is set in a niche.