Facebook has opened its fifth engineering office, this one in the tech-centric Kendall Square of Cambridge, Mass. It’s being called “the one that got away.” Though Mark Zuckerberg founded the company at Harvard, it’s taken nine years for Facebook to set up an official presence in the Bay State.

A handful of Facebook employees have been working remotely from Boston, though. In a blog post, Ryan Mack, who will head the office, says that their work has included the infrastructure behind the Timeline and Photos products. The Cambridge team will be small, and beyond that Facebook isn’t providing any details about headcount. So far, the company lists only one opening at that site: software engineer, infrastructure. It has said the team will focus on four core areas: networking, compilers, security and storage. “We are in Boston because there is really great, deep technical talent, and great startup culture,” Mack told the Boston Globe. “We really have to invest heavily in hiring really strong talent.” Facebook’s other engineering outposts are in Seattle, London and New York, as well as at its headquarters in Menlo Park, Calif. While Facebook has recruited heavily at Harvard and MIT, up to now it’s hiring has focused on positions at those other locations. “In order to reach [all these people] and provide a fast, good user experience, the infrastructure we build has to extend across the globe. We need to optimize the net protocols, bandwidth for mobile devices. Most of those billions that are not yet connected will skip the desktop and PC and move right to smartphones, that brings challenges in load balancing and optimizing protocols over cell phone connections” Jay Parikh, vice president of infrastructure engineering at Facebook told GigaOM. Facebook’s new office is in the same building as the Cambridge Innovation Center, a shared workspace for more than 300 entrepreneurs and small businesses.