St Gallen Abbey has been marking 25 years since it was made a Unesco World Heritage Site.
Officials said St Gallen did not even have to officially apply for the accolade, it simply received a call from the capital, Bern, asking if it wanted to be included.
"St Gallen said it did," said local parliamentarian Kathrin Hilber during a speech to mark the occasion on Saturday, the first of two days of festivities. "We received the title quickly, but we want to use it with pride and respect and to keep it for future generations," she added.
The Baroque cathedral, described as one of the most beautiful of its kind, forms one part of the St Gallen World Heritage site. In addition, there is the ancient Abbey Library, which contains thousands of rare books, including many more than 1,000 years old. Up to 7,000 people visited the site over the weekend.
Pierre Galland, vice president of the Swiss Unesco Commission, was among those to offer their congratulations. He particularly praised St Gallen's renovation work and its new heritage preservation charter.
Also celebrating a quarter century as a world heritage site this year are Bern's old town and the St Johann Müstair Monastery in the eastern canton of Graubünden.