Larry Page and Sergey Brin founded Google in 1998 after developing a search engine called BackRub while PhD students at Stanford University. They registered the google.com domain in 1997 and formally incorporated Google in 1998 in Susan Wojcicki's garage in California. As of 2015, Google employed over 57,000 staff worldwide and owns data centers across the US, Asia, and Europe powered by renewable energy. In 2015, Page and Brin established Alphabet as the parent company of Google and other subsidiaries.