The Stelling van Amsterdam was the most advanced military structure of its type in the world - 135 km (84 miles) of forts, batteries and moats completely encircling the city in a defensive barrier.
On the cliff face of a sandstone mountain, visible from the ancient Silk Road near the town of Bamiyan in Afghanistan, are two massive voids left by two monumental statues of Buddha that once stood there.
Kupari was once a hugely popular holiday resort, until it was damaged during the Croatian War of Independence.
Tucked away in the Caucasus Mountains in the north of Georgia, is the historic province of Khevsureti.
Checkpoint Charlie was the name given by the Western Allies to the best-known Berlin Wall crossing point between East Berlin and West Berlin during the Cold War.
The Berlin Wall was a guarded concrete barrier that physically and ideologically divided Berlin from 1961 to 1989.
In the early l950s, RAF Barnham was selected for development as a dedicated storage and maintenance facility for nuclear weapons, in particular for Blue Danube, Britain's first nuclear bomb.
Unlike other notorious barriers in the world, the Moroccan Wall is rarely in the news and is little discussed outside of Africa. The existence of this wall has been buried in the desert, along with the 40-year-old plight of the Sahrawi people the Moroccan Wall has kept divided.
About 25 miles south of Berlin lies the small town of Wunsdorf, home to about six thousand inhabitants. But less than thirty years ago it had a population of sixty...
For many years, these bizarre buildings on the isolated southern tip of Marco Island in Cape Romano, Florida, were a bit of a mystery.
Hadrian's Wall was a defensive fortification in Roman Britain, begun in AD 122 during the rule of emperor Hadrian. In addition to its military role, gates through the wall served as customs posts.