Dover in the United Kingdom
The underground structures found in Dover in England may not be as impressive as some of the cities on our list, but the structure itself has a curious history to share with the world. Nestled below a prominent castle in the region, this structure was primarily used by the Royal Army Medical Corps in World War II. Over and above this, it also played an important role during the Dunkirk evacuation, which saw allied soldiers depart from the beaches and harbor in the area between 26 May and 4 June in 1940. History aside, it contains some exquisitely crafted steps and crevices too.
Scotland in the United Kingdom
The Edinburgh Vaults in Scotland are an underground labyrinth that lurks eerily beneath the surface of the city. Interestingly enough, this network of tunnels was built underneath Edinburgh’s South Bridge in the 1700’s, initially intended just to be used as a storage facility for merchants. As needs have changed over time, it has been used for a range of different things. At some point between its creation and the 20th century, it was sealed off in what officials at the time thought would be permanently. Much to the delight of British historians, it was accidentally rediscovered again in the 1980’s.