1. Melk Abbey
Melk Abbey is a remarkable Benedictine abbey, towering over the town of Melk in Austria's Wachau Valley. You might look at the abbey's Baroque grandeur and wonder if it's all a little excessive for people of the cloth. The abbey you see today was actually built in the early 18th century as a royal palace, on the site of an ancient monastery.
The abbey is well known for its library, which houses over 100,000 rare and valuable books. The main hall shows off just a percentage, but you certainly get the idea as you gaze at 16,000 volumes and a wonderfully frescoed ceiling. You can take in centuries of art and religious antiquity on a guided tour of this magnificent monastery.