RAF Menwith Hill
No these aren’t golf balls, they are actually the hub of intelligence and surveillance worldwide. It is home to multiple satellites operated for reconnaissance purposes for the United States of America. To think that a large chunk of U.S. intelligence depends on these round structures would be an understatement. It also takes the prize for being arguably, the best hidden, and elusive configurations in Europe. That other characteristics enable to heightened comms and intel to a large chunk of the first world. What does this say for public access? Well you can’t sneak in, because there’s a chance that you’d be detected by one of many (if not multiple) satellites this hub is in direct control of.