SAN FRANCISCO - Google Inc. is opening a virtual window into the secretive data centers where an intricate maze of computers process Internet search requests, show YouTube video clips, and distribute e-mail for millions of people.

The unprecedented peek is being provided through a new website unveiled Wednesday at The site features photos from inside some of the eight data centers that Google already has running in the United States, Finland, and Belgium. Google is also building data centers in Hong Kong, Taiwan, Singapore, and Chile.

Virtual tours of a North Carolina data center also will be available through Google's Street View service, which is usually used to view photos of neighborhoods around the world.

The data centers represent Google's nerve center, although none is near the company's headquarters in Mountain View, Calif.

As Google blossomed from its roots in a Silicon Valley garage, cofounders Larry Page and Sergey Brin worked with other engineers to develop a system to connect low-cost computer servers in a way that would help them realize their ambition to provide a digital road map to all of the world's information.

Initially, Google just wanted enough computing power to index all the websites on the Internet and deliver quick responses to search requests. As Google extended into other markets, the company had to keep adding computers to store videos, photos, e-mail, and information about their users' preferences.

Google studies Internet search requests and Web surfing habits in an effort to gain a better understanding of what people like. The company does this in an effort to show ads of products and services to the people most likely to be interested in buying them. Advertising accounts for virtually all of Google's revenue, which totaled nearly $23 billion through the first half of this year.

Even as it allows anyone with a Web browser to peer into its data centers, Google intends to closely guard physical access to its buildings.