( CNN ) -- Moored on the waters of San Francisco Bay , just east of Alcatraz and the Golden Gate Bridge , is -- well , a mystery . Atop a barge docked at Treasure Island , site of a former Navy base , is a four-story structure made from shipping containers . The purpose of the structure remains unknown , but the safe money says Google is up to something on board . Officials wo n't say exactly what 's going on there . But some sleuthing by the media in the tech-heavy Bay Area has pretty much nailed down that Google , headquartered about 40 miles south in Mountain View , California , is behind the project . Tech blog CNET reported as much on Friday , citing lease agreements , Treasure Island locals and `` tracking a contact tied to the project on LinkedIn . '' News reports say an unknown company has been working on a major project , under tight security , in a hangar on Treasure Island since last year . Witnesses say materials from that hangar were transferred onto the barge . Google did not respond to a request to comment for this story . So , even if the suspicions about Google and the barge 's mysterious cargo are correct , that leaves the obvious question : What are they building in there ? Early speculation has centered on a data center . Google has banks of servers stored in warehouses all over the world , and floating data centers are n't unheard of . Sitting on that much water would provide an obvious source of cooling , which is a big concern for data centers , and possibly even a source of power . And Google has a patent for such a project . But San Francisco station KPIX , a CNN affiliate , threw a twist into the narrative , quoting unnamed `` sources close to the project '' as saying the structure will be retail space -- a sort of floating Google store . Google hopes to tow the structure across the bay to San Francisco , where it would be used to market Google Glass , the company 's connected eyewear , KPIX reported . Google Glass , the company 's big leap into wearable technology , puts computer capabilities into eyeglasses . The headsets so far have been released only to early testers and are expected to go on sale to consumers in the coming months . An official with the San Francisco Bay Conservation and Development Commission told KPIX that there have been discussions with Google about `` hypothetical operations '' on the bay . But work on the project suddenly stopped a few weeks ago . One possible reason : An insider close to the commission told KPIX that Google `` ca n't park this barge on the waterfront without a permit , and they do n't have one . ''
` ` Mystery barge '' on San Francisco Bay may be a Google project . Barge holds mysterious four - story structure . Project centers on data center , possible marketing site for Google Glass . Google has not responded to requests for information .