From mighty landmarks like the Great Wall of China to the poignant Vietnam Veterans Memorial, walls have protected, divided and commemorated nations and people for thousands of years. These mighty constructions continue to fascinate us with their intriguing pasts.

Click through the gallery as we delve into the world's most famous walls and their fascinating secrets...

An hour's drive up the coast from tourist hotspot Dubrovnik, on the Pelješac Peninsula, lies one of the longest defensive walls in the world – the Walls of Ston. They guard the medieval towns of Ston and Mali Ston, whose marshy lands provide wealth in the form of salt flats. In 1333, after the Republic of Dubrovnik purchased the peninsula from Serbian Emperor Dušan, they built the 4.3-mile (7km), 40-tower, five-fort construction with the help of a Florentine architect. 

A stroll around the Walls of Ston – which have around 3.4 miles (5km) and 20 towers remaining – is complete in under two hours. The Ston section takes just about 15 minutes, while a hike over the hill to Mali Ston adds on an extra 30 minutes. The area is also known for its stellar seafood restaurants, with mussels and large flat oysters having been harvested in this area since Roman times.

Just northeast of the Lincoln Memorial, on DC's National Mall, is the Vietnam Veterans Memorial, paying tribute to Americans who were killed or went missing in the Vietnam War. It was designed by American artist Maya Lin, aged just 21 and an undergraduate at the time. Lin’s simple, granite, V-shaped design is a poignant tribute to those who were lost in the conflict.

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At the emotional site, two 246-foot (75m) long walls, with inscriptions of the names of 58,318 servicemen who sacrificed their lives, meet at an angle to form a V shape. Between 1955 and 1975, the US allied with South Vietnam and fought communist North Vietnam – a war that saw lives lost on both sides and divided the country. Now each year thousands of people gather on Memorial Day and Veteran's Day to hold ceremonies.

The Berlin Wall was built in the 1960s to prevent those in communist East Germany from travelling – or escaping – to West Germany. Known as the "Antifaschistischer Schutzwall" in East Germany, which translates as the "anti-fascist barrier", it divided families and caused an exodus before it went up. During the Cold War it's thought 327 people died trying to cross the border – some were shot, some drowned, while others set off mines or accidentally suffocated in the boots of cars. In 1989 the wall finally came down. Pictured is an elderly woman talking to her East Berlin friends and relatives in the early 1960s.

Today art lovers are drawn to the East Side Gallery, the longest remaining stretch of the Berlin Wall, and now a monument to freedom. Visitors can take in the colourful murals, including the famous Kiss, on this 0.8-mile (1.3km) tribute to liberty. The Mauerpark, once the wall's off-limits border strip, is now home to a weekly flea market too. 

Most visitors to Berlin will also swing by Checkpoint Charlie – the most famous controlled border crossing at the Berlin Wall. The barrier and booth remain and it's also home to the Mauermuseum, which includes artefacts that tell the stories of those who successfully made it over the border. 

In the Peruvian Andes, north of Cusco – once the capital of the Inca Empire – are the mysterious Sacsayhuamán ruins. A jigsaw of huge stones, cut to precision, make up the hulking mortar-free walls of the Inca fortress. When it was built remains a mystery: the foundations of an earlier site may date from AD 900 to 1200, but the current walls are likely to have been built in the 15th century. Yet when the Spaniards invaded 100 years later, presumably equipped with more resources than the Incas, they were unable to demolish it.

A visit to the Sacsayhuamán ruins is a popular choice for those staying in Cusco. Besides offering wonderful views over the Peruvian city, this UNESCO World Heritage Site has much to marvel at. Its magnificent megaliths, the largest of them weighing 300 tonnes, are arranged in three tiers – an inspiring feat of early engineering. 

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The ancient city of Troy in Turkey, now little more than ruins, is believed to be the real-life location of Homer’s epic poem "the Iliad". It's thought to have been written in the 8th century BC, narrating the Trojan war that took place some 400 years earlier. In Homer's version of the story, the spartan queen Helen was taken from her Greek husband Menelaus by Paris of Troy, triggering a 10-year siege on Troy.

Visitors to the ghostly ruins will find archaeological remains of the Greeks and Romans, not just Trojans. Countless citadels and fortifications piled on top of each other give evidence for as many as seven settlements here. However, Troy was also a spectacularly complex city with an upper and a lower level, roads, trenches and walls. 

Great Zimbabwe was once the capital of the Kingdom of Zimbabwe, inhabited from 11th to the 15th century by the Shona, an African Iron Age civilisation. Around 18 miles (29km) from modern-day Masvingo, the then-sophisticated city traded in gold and had unparalleled architecture including turrets, towers and staircases. The Great Zimbabwe wall that protected the city still towers over its ruins today.

It's still possible to stroll around the 36-foot (11m) high wall and visualise the city it encased, which reached a population of up to 18,000 at its height and traded with cities from Arabia and China. 

The ancient walls of Istanbul – also known as The Walls of Constantinople – are often said to be among the most important in Western history. They were formally started by Emperor Constantine – who ruled between AD 306 and 337 – to defend the city, at the time known to the Romans as Constantinople. At least 20 times the size of London, it was an important seat of learning and culture thanks to its universities and libraries, plus it enjoyed huge wealth due to its place on trade routes from the East. 

Emperor Theodosius II built additional sections of the walls in the early 5th century. The now lengthy fortification included a moat, a short wall where archers would be stationed, a 27-foot (8m) long outer wall (from which incendiary weapons such as Greek fire were used to fend off invaders), plus a great inner wall wide enough for four men to walk side by side, in case the outer wall was compromised. The city walls were so strong they weren't breached until 1453 by a cannon. 

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Today, a walk around The Walls of Constantinople can take under two hours, depending on how distracted wanderers get along the way. The walls remain largely intact, minus a few sections which were dismantled in the 19th century when the city expanded.

The chewing gum wall in Seattle’s Pike Place Market is a funny sight. A splash of different coloured gum covers the wall, with some pieces stretched or shaped into messages. Pictures and mementos are also glued up. It all began in the 1990s, with theatre-goers sticking their gum to the wall while waiting for shows. In 2015 the market management tried to clear it up, steaming a total of 2,350 lbs off the wall, but the very next week people were right back at it.

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Some think it’s cool, others may say it’s revolting, but the 50-foot (15m) long wall has become a tourist attraction in Seattle. On a sunny day hundreds of tourists can typically be seen taking pictures while chewing gum and blowing bubbles in front of the wall, each leaving their little mark. Over the years, prom date requests and marriage proposals have also happened in front of the unique landmark. 

A long-time haunt for pacifists and dreamers, a wall dedicated to peace, love and John Lennon takes up a quiet corner of Prague. Following the assassination of the Beatles legend in the 1980s, an image of his face was painted on a wall close to the French embassy. Soon after political messages, peace signs and Beatles lyrics were scribbled alongside it, until it was a kaleidoscopic mural that's lasted for decades.

Over the years, the musician's enigmatic face has been weathered away by graffiti and doodles – often declarations of love and liberty, though sometimes profanities from late-night revellers. Now the long-standing communal mural is being transformed into a space for professional muralists to display their works – still, perhaps, with a dedicated corner for amateur artists and die-hard Beatles fans.

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One of the most recognisable walls in history, the Great Wall of China stretches across the country’s northern border, from Shanhaiguan in the east to the Gobi Desert in the west, running for more than 13,000 miles (20,921km). Designed to protect both Chinese land and culture, its sections were linked together from the 3rd century BC to the 1600s – although some foundations and parts are believed to date as early as the 7th century BC. Over time it's been repaired and rebuilt, most famously by the Ming dynasty (1368-1644) who added garrisons and watchtowers. 

Today, the Great Wall of China is a UNESCO World Heritage Site, although about one third of it has disappeared. Mutianyu is the most popular section for tourists: visitors head there to see its formidable watchtowers and fortress restored to their former magnificence. Alternatively, some prefer to get off the beaten track at Jiankou (pictured), where the wall winds down the steep mountain ridge. Simatai, with its illuminated nighttime lanterns, is another quieter spot.

Inner Mongolia plays host to some of the wall's oldest sections, including the Zhao Great Wall, dating from the 4th century BC. Yadan National Geological Park (pictured), in the Gobi Desert, is where visitors can find the Han dynasty Great Wall dating from the 1st century BC, along with the Jade Gate Pass. It got its name from the Khotanese jade that passed through here along the Silk Road. The area is also filled with otherworldly rock formations.

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A recent study has revealed that warrior princesses prompted China to build the Great Wall in the first place. It seems these women played a crucial part in the success of the Xiongnu Empire, after archaeologists studying graves in the foothills of the Altai Mountains found the biggest, mounted tombs belonged to important, high-ranking females. They discovered bronze chariot pieces, gold discs and remains of sacrificed livestock all inside elaborately decorated coffins which had golden sun and moon symbols (pictured).

Hadrian’s Wall spans 73 miles (117km) across the width of Britain, and was built between AD 122 and 128 on orders from the Roman emperor Hadrian – his intention was to protect the Roman Empire’s most northern border from so-called Scottish "barbarians". 

Hadrian's Wall is a mighty symbol of Roman tenacity and still lies remarkably intact. Visitors can delve into its fascinating history by retracing the footsteps of its engineers some 2,000 years ago. It’s possible to walk the whole trail, which would take around five days. The best time to visit is March to October, when the weather is pleasant and the land is not too slippery. 

Those that haven’t got all week can also start at the Roman Army Museum near Brampton, Cumbria and walk the roughly 10-mile (16km) stretch of mostly intact wall to Housesteads Fort (pictured). This takes trekkers through some of the most dramatic landscapes the wall has to offer, before winding up at the ruins of an old Roman fortress. This tourist hotspot once encompassed an ancient hospital, barracks and toilet, and also grants views over Northumberland National Park.

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