Paris, France | Google has signed up with 18 Loire Valley chateaux to create virtual tours of the former royal dwellings, the Internet giant's Cultural Institute said.

"Not everyone is fortunate enough to be able to travel to the Loire Valley to see these wonders with their own eyes," the Paris-based institute said in a statement.

Thanks to Street View image capture technology, people can take virtual tours of Chenonceau, Chambord, Azay-le-Rideau and 15 other of the national treasures strung along the Loire in central France, including spaces that are normally off-limits to the public.

Seven of the sites can be overflown in three dimensions.

Another technology, Art Camera, homes in on details of an artwork that are invisible to the naked eye, such as the Oriental ceiling of the Villandry chateau, the Apocalypse Tapestry of Angers and the frescoes of Fontevraud Abbey.

The new technology provides even greater resolution than Gigapixel, which Google has used to digitise artworks.

Google has similar agreements with more than 1,000 museums and cultural institutions in more than 60 countries around the world.