The Underground White House

"In 2010, tall fences went up outside the West Wing of the White House and a massive construction project was underway. Officially, the construction project was described as a much-needed infrastructure systems replacement. The massive scope of the project, described as a "sprawling, multistory structure whose underground assembly required truckloads of heavy-duty concrete and steel beams", led to many questions and conspiracy theories. Was this a new presidential command center housing its own massive communications data center? One official stated off the record "It is security-related construction."

There are rumors of tunnels connecting the White House to the Capitol, Blair House, VP Residence, Camp David and the Pentagon, but these are unsubstantiated at this time. "

https://whitehouse.gov1.info/tunnel/