The closest is Palais Equitable, 1 km south-west of the city centre; the most famous is Schönbrunn Palace — #17 of 8,133 worldwide — 5 km south-west. The oldest dated site in the circle is Gerulata, founded c. 150.
The 100 km circle reaches into 4 countries — Austria (79), Slovakia (29), Czech Republic (9), Hungary (6).