London’s long-hidden wartime tunnels beneath Holborn are set to reopen by 2028 as a major tourist attraction. Once a hub for WWII intelligence and Cold War communication, the 90,000 sq. ft. site will feature a relocated military museum, immersive exhibits, and the world’s deepest underground bar. This revival offers visitors a rare look at Britain’s covert past, blending espionage history with cultural experiences in one of London’s most anticipated attractions.