The closest is Racibórz Castle, 20 km west of the city centre; the most famous is Jasna Góra Monastery (#164 of 9,035 worldwide) 91 km north-east. The oldest dated site in the circle is Będzin Castle, founded c. 1050.
The 100 km circle reaches into 3 countries: Poland (50), Czech Republic (13), Slovakia (3).