Take a Panoramic Virtual Tour of Smithsonian National Museum of Natural History. Available as a full-screen virtual tour starting entry rotunda and navigating from there, or jump to individual rooms.
The Nottingham Cave Survey is active program that is recording all of Nottingham's 450+ sandstone caves, using a laser scanner to capture 3D details of the caves. So far, there are over 100 clips on YouTube, most of them flythroughs into the caves. Many clips are short, some clocking under a minute, while others run over 10 minutes, such as the tour of the private Peel Street Caves (Rouse's Sand Mine [PDF]).
Aerial Virtual Tour of New York City -- navigate with your arrow keys (or the embedded controls). Change views on the lower left. [via Gothamist]
'I am Mahabir Pun. I would like to take you on a tour of my village (Nangi), and my country (Nepal and the Himalayas). I would like you to learn about our High School in Nangi Village, Nepal. Some people from abroad have visited and worked in Nangi and have interesting stories to tell you of their time here. '
Psychophysical spaces - the tuberculosis sanatorium of Paimio, Finland from the beginning of thirties. Explore Alvar Aalto's soothing Scandinavian functionalism on a detailed virtual tour.
Tour the Nasher Sculpture Garden. Can't make it to Dallas. Big D is now home to the one of the first institutions in the world dedicated exclusively to the exhibition of modern and contemporary sculpture with a collection of global significance as its foundation. The Nasher Sculpture Center is further distinguished by a groundbreaking facility and landscaped garden specifically designed for the indoor and outdoor display of sculpture - not to mention the "designer dirt". (flash)
Pick your poison: highbrow (virtual tour of 10 Downing Street), or lowbrow (virtual tour of the White House). Hint: one of these is funny.
Inside the House : A virtual tour of the Sydney Opera House. [Note: Flash]
Tour Egypt. "Egypt is an exciting country, both for its antiquities, and modern high culture. Tour Egypt is an Egypt guide with over 10,000 pages of information about every aspect of travel, ancient and modern Egypt." Two of my favorite links are the Hieroglyph Converter and Ikhernofret's Description of the Osiris Passion Play at Abydos. The current feature is about the Monastery of Jeremiah at Saqqara . Actually, quite a nice resource.
The Virtual Tour of Edo allows you explore the city that would one day become Tokyo, Japan. Classical images illustrate short descriptions of life in this 18th century metropolis. Although modern Tokyo may look very "Western" on the surface, in its heart the spirit of Edo still lives on!
The Temple Expiatori de la Sagrada Família in Barcelona is a breathtaking masterpiece. Most of the pictures are worth clicking to see the full view. (And the virtual tour with IPIX is pretty cool. Make sure you pan around.)