When it comes to protecting themselves from what they fear, humans have a real knack for building walls and fences. The U.S. has been busily building a fence along its border with Mexico to discourage illegal immigration and smuggling. Not to mention, the recent reform bill passed by the Senate could greatly accelerate that construction. But this desire to keep others out predates America by at least 2,000 years. Here's a look at some of the most notorious barriers we've built, from China to Berlin and beyond.
THE GREAT WALL OF SAND
This 1,500-mile wall was built in the 1980s by the Moroccan army to ward off attacks from the Polisario Front, a guerrilla group seeking independence for the Western Sahara region. As the conflict evolved and the Moroccan army pushed deeper into the guerrillas' stronghold, troops took down the sand wall and moved it several times! The great wall of sand still exists. It now starts at Morocco's southern border with Mauritania, stands nine feet high and is supplemented with anti-personnel radars, infantry units, mines and artillery.
THE WEST BANK BARRIER
This 400-mile combination of walls and fences divides Israel from the West Bank Palestinian territory. Israel's government began to construct this barrier at the height of the second intifada, in 2002. Eleven years later, the barrier is almost complete, and it has become one of the most controversial border security projects in the world. Israel calls the barrier a "security fence," claiming it has helped to reduce attacks by Palestinian terrorists on Israeli towns and settlements. Palestinian activists call the barrier an "apartheid wall." They say the wall has served as an excuse for stealing Palestinian land and made life difficult for Palestinians who work over the border -- including thousands who were separated from their farmlands.
It's not exactly a wall but more like a heavily patrolled border zone lined with guard towers, barbed wire and numerous fields carpeted in landmines. The demilitarized zone is 160 miles long and 2.5 miles wide. It was established after the 1953 Korean War Armistice, to prevent North Korean and South Korean forces from getting too close to each other. The DMZ's crazy features include a conference building right on the borderline, where one half of the main room is in North Korea, and another half in South Korea. There's also a propaganda village on the North Korean side of the DMZ made up of shiny but empty buildings, which were built to make South Koreans think that life was good in the north. Since it was established, South Korean forces have discovered four different tunnels built to allegedly help North Korean agents bypass the DMZ for mischievous missions.
THE BERLIN WALL
During the 1950's, some 3.5 million dissatisfied residents of East Germany defected from the communist country by crossing into the capitalist stronghold of West Berlin. The East German government reacted to this embarrassing problem by building the Berlin Wall, with construction starting in 1961. At its most developed state in the late '70s, the Berlin Wall was up to 12 feet high. There were 116 watchtowers along the wall, which was also surrounded by a 100-yard-wide death strip -- a flat area with no buildings, where anyone approaching the wall could be easily shot by border guards. Despite such dangers, an estimated 5,000 people attempted to illegally cross the wall during its 28-year lifespan. Historians estimate that at least 600 people died in the attempt.
BELFAST'S PEACE WALLS
In Belfast, the capital of Northern Ireland, there are 40 barriers separating Catholic and Protestant communities. This network of barriers is about 13 miles long and is known as the Peace Walls. The barriers were initially built in 1969, following a spate of sectarian riots that led to years of conflict between the religious factions. Some local residents, who still fear violence from neighbors with opposing views and different religions, want the barriers to stay.
Built by the Roman emperor Hadrian in the second century AD, this stone barrier cuts across a narrow coast-to-coast section of northern England. Some historians say the wall had something to do with warding off attacks from Scottish tribes. Others believe that the 70-mile barrier was built to make it easier for the Roman government to tax goods going in and out of this remote corner of their empire.
THE DUBROVNIK WALLS
Located in Croatia, these massive fortifications were built between the 8th and 17th centuries. For some of this time, Dubrovnik was the capital of the Republic of Ragusa, a small country that no longer exists. The tiny republic was quite fond of walls. It also built a 5 km long wall that split a nearby peninsula in to two and protected its valuable salt-flats. Salt was one of the Republic's main products.
THE GREAT WALL OF CHINA
It's the granddaddy of all border walls, fences, and defense systems, but contrary to popular belief, we're not just talking about a single wall here. The term Great Wall of China actually refers to a series of fortifications built by several Chinese dynasties, from the 8th century BC to the 15th century AD. The walls, which measure at least 5,000 miles, helped to ward off invasions from northern peoples like the Mongols and the Manchus. But that didn't always work. The Mongols made their way around the wall in the 13th century and conquered Beijing, establishing the Yuan Dynasty. In 1644 the Manchus crossed the wall and established their own dynasty as well.