Somehow it's possible to hide a 1,120-acre research park with more than 2 million square feet of corporate offices, labs and university classrooms inside the capital. Inside the Beltline even. N.C. State University is celebrating the 25th birthday of its innovative Centennial Campus today as it breaks ground on a new library that is expected to be its aesthetic and cultural heart. The campus is revered elsewhere in the world, but many locals aren't aware of what it has become, said Tom Rabon, an executive vice president of Red Hat, the software company with headquarters on Centennial. About three years ago Rabon was invited to Toulouse, France, to talk about the place his company had picked for its headquarters. "The French government paid me to come over and talk about nothing but Centennial Campus because they wanted to emulate exactly what we have," he said. "People in Raleigh drive past every day and just have no idea what's behind that line of trees on I-40, and no idea that Centennial Campus is the envy of the world."