You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Alps

Context:
Christianity was established in the region by the Romans, and saw the establishment of monasteries and churches in the high regions. The Frankish expansion of the Carolingian Empire and the Bavarian expansion in the eastern Alps introduced feudalism and the building of castles to support the growing number of dukedoms and kingdoms. Castello del Buonconsiglio in Trento, Italy, still has intricate frescoes, excellent examples of Gothic art, in a tower room. In Switzerland, Château de Chillon is preserved as an example of medieval architecture.

Question:
What is preserved as an example of medieval architecture?

Château de Chillon