Three months ago, the Trump administration broke ground on its highly controversial plans to add a sprawling ballroom to the White House’s East Wing. Plans to rebuild an underground shelter that could once again provide protection for key White House officials have been shrouded in plenty of secrecy. The complex was a “very complicated submarine that was built in the 1940s — a self-contained unit, [with] separate power backups, separate water backups, separate air filtration,” a source told CNN. “But all the infrastructure is 1940s infrastructure.”A separate source confirmed to the broadcaster that “all of the subterranean structures,” including the bunker, have been gutted as well. “We’re never going to get the line of sight on how much that costs.”More on the White House: Simulation Found Civil War Could Be Triggered by Exactly What ICE Is Doing Right Now