The Castle of the Warmian Chapter in Olsztyn — a Gothic 14th-century castle (1346) where Nicolaus Copernicus served as administrator from 1516-1521. Here he made his famous astronomical Sun-position measurement tables — preserved to this day on the cloister wall.
In the castle Copernicus defended Olsztyn against the Teutonic Knights in 1521. You can visit his apartments, astronomy room, lecture hall.
Museum of Warmia and Masuria — rich collection of regional art, Prussian archaeology, cultural heritage. Cloisters with stone sculptures.
Open Tue-Sun 10:00-17:00. Ticket 18 PLN. Audio guide PL/EN/DE/RU.