The Votivkirche (Votive Church) is a neo-gothic church in Vienna, Austria. It was being remodeled when I was visiting, but much of the cathedral was still accessible. The church was built as a thanks to God when the Austrian Emperor Franz Joseph survived an assassination attempt in 1853. His brother helped raise the funds and it was dedicated in 1879. The church was badly damaged during World War II and has had various renovations since then. Wikepedia has some detailed information on the interior as well.
Melk Abbey is about an hour’s drive from Vienna, Austria and was founded on an rocky overlook in 1089 when the former castle was gifted to the Benedictine monks by Leopold II of Austria. The abbey has had several fires and suffered severe damage from invading Turks, but was largely rebuilt in 1702. It’s a Baroque complex that includes a school and museum and is a popular tourist spot these days.