Only two hours outside of Paris, Chateau de Chambord is the largest chateau in the Loire Valley, but it remains unfinished. It was originally built as a hunting lodge for King Francois I and is massive!
Once Francois passed away the chateau was left abandoned for nearly 100 years. Various architects across the ages have worked on it and it is interesting to see the various styles while touring the property.
Since the French government took it over and began restoring it, the chateau and its grounds have become extremely popular - there are over 100 rooms to explore if you like.
Add on to the grounds that are extensive and you can spend (and you should) an entire day here.