“Dover Castle is a medieval castle in the town of the same name in the English county of Kent. It was founded in the 12th century and has been described as the “Key to England” due to its defensive significance throughout history. It is the largest castle in England.

The outbreak of the Second World War in 1939 saw the tunnels converted first into an air-raid shelter and then later into a military command centre and underground hospital. In May 1940, Admiral Sir Bertram Ramsey directed the evacuation of French and British soldiers from Dunkirk, code-named Operation Dynamo, from his headquarters in the cliff tunnels”. – Wikipedia

Photo: The Repeater Station in the subterranean tunnels underneath Dover Castle, which has been restored by English Heritage for a public exhibition on June 3, 2011 in Dover, England. The evacuation of allied soldiers from Dunkirk was masterminded and co-ordinated from the secret command and control centre in the tunnels deep below the castle. (Photo by Matthew Lloyd/Getty Images)

“Lombard Street is an east-west street in San Francisco, California. Lombard Street is best known for the one-way section on Russian Hill between Hyde and Leavenworth Streets, in which the roadway has eight sharp turns (or switchbacks) that have earned the street the distinction of being the crookedest street in the world”. – Wikipedia

Photo: A single car drives down a typically crowded Lombard Street, San Francisco's crooked street, April 29, 2003 in San Francisco. (Photo by Justin Sullivan/Getty Images)

The hot air balloon “Hopper T Frog” from Park City, Utah, peeks over the red rock cliffs during the 23nd Annual Red Rock Balloon Rally at Red Rock State Park December 6, 2003 near Gallup, New Mexico. (Photo By Douglas Tesner/Getty Images)

A light railway train passes through a residential building on March 18, 2017 in Chongqing, China. Chongqing Rail Transit No.2 and a 19-storey residential building have been built across each other. The railway set its Liziba Station on the sixth to eighth floor in the building with noise reduction equipment. (Photo by VCG/VCG via Getty Images)

Farmers work on a farm near a construction site of new residential buildings in Shanghai, China, February 20, 2016. (Photo by Aly Song/Reuters)

A woman walks inside a building in downtown Havana, Cuba April 21, 2016. (Photo by Alexandre Meneghini/Reuters)

Yaroslav Segeda at the top of a high rise building in Kudrinskaya Square, Moscow, Russia. (Photo by Yaroslav Segeda/Caters News)

A Palestinian woman argues with an Israeli border policewoman over the Israeli demolition of a building housing an apartment and a restaurant as the building owners said they were informed by the forces that they did not obtain a construction permit, in Beit Jala in the Israeli-occupied West Bank on August 26, 2019. (Photo by Mussa Qawasma/Reuters)