Google began in March 1996 as a research project by Larry Page and Sergey Brin, who were Ph.D. students at Stanford working on the Stanford Digital Library Project, also known as “SDLP”. The goal for “SDLP” was to “Develop the enabling technologies for a single, integrated and universal digital library.” Larry page started his research with a project nick-named “Backrub”, and was soon joined by Sergey Brin. Originally their search engine project used the Stanford website with the domain google.stanford.edu. On September 15th of 1997 Larry and Sergey registered the domain Google.com. Google, Inc. was formally founded on September 4, 1998 at a friend's garage in Menlo Park, California. The name "Google" originated from a misspelling of "googol," which refers to the number 1 followed by one hundred 0’s. The verb, "Google" was added to the Oxford English Dictionary in 2006, meaning, "to use the Google search engine to obtain information on the Internet." By the end of 1998, Google had an index of about 60 million pages, even though it was still in “BETA” stage. After quickly outgrowing two other sites, the company leased a complex of buildings in Mountain View at 1600 Amphitheatre Parkway from Silicon Graphics (SGI) in 1999. The company has remained at this location ever since, and the complex has since become known as the GooglePlex. A “Googolplex” is a term referring to a googol. In 2006, Google bought the property from SGI for $319 million.