6. Fort de Douaumant, France
This fort was one of 19 such buildings constructed around the town of Verdun in northern France. Because the forts dated from the 1890s, the modern warfare and weapons of World War I completely overwhelmed them: Fort du Douaumont was occupied without struggle by a small German troop in February 1916. The 9-month Battle of Verdun ensued, tragically costing the lives of countless young men.
Dominating the little fishing village of Bamburgh on the Northumberland coastline, Bamburgh Castle still has its Norman core. Primarily the seat of the English monarch over the years, it was an occasional target for Scottish raids and has belonged to the Armstrong family since 1894. It’s open to the public, and is a very popular wedding venue.
8. Citadel of Aleppo, Syria
Considered the oldest and largest fortress in existence, Aleppo’s citadel sits on a mound that has been inhabited since – incredibly – the middle of the third millennium BC. The citadel is surrounded by a deep moat, and inside there's a remarkable amphitheatre, palace, hammam and underground passages.
Baba Vida Fortress is named after Vida, the eldest daughter of a nobleman who left his lands and powers to his three girls. Kula and Gamza married badly, while Vida refused all proposals, instead concentrating her efforts on constructing this fortress. Simply designed but oh-so-effective, with four towers and two thick grey walls, the fortress is now a fascinating museum.
10. Kumbhalgarh, India
India has plenty of remarkable fortresses, but what makes Kumbhalgarh Fort in Rajasthan so special is its beautiful evening light show, when its bulbous gates and curving ramparts are bathed in an orangey glow. Built in the fifteenth century and the birthplace of the great warrior Maharana Pratap, the fortress protects hundreds of shrines and the highlight, the painted Badal Mahal (Palace of Cloud).
11. Spiš Castle, Slovakia
Due to its rocky ruins, rambling ramparts and glorious views from its hilltop location, Spiš Castle in Slovakia has starred in a selection of medieval-era films such as Dragonheart and the Last Legion. Built over an original settlement in the twelfth century, the castle has had a long and tumultuous past, but burnt down to its current clapped-out state in 1780.
Prague Castle is the jewel in the crown for the Czech Republic, and in fact houses the Czech Crown Jewels themselves. The fortress is an attractive collection of palaces and ecclesiastical buildings, all displaying different architectural styles – like the Gothic St Vitus Cathedral and Romanesque Basilica of St George.
A haven of green fields and trickling canals, and shaped like a star, Bourtange Fort looks far from martial. William of Orange commissioned the fort during the Eighty Years War (1568–1648) but by 1851 it had been transformed into a peaceful village. The fort now looks as it did during the eighteenth century, but is now a diverting open-air museum.
14. Himeji Castle, Japan
One of the prettiest buildings you’ll ever see, Japan’s Himeji Castle is often referred to as the “White Heron Castle” for its resemblance to a flying bird. It has 6 stories, 83 rooms and a serene inner moat, and has the auspicious claim of being Japan’s premier and most popular castle. It’s currently undergoing extensive renovation, due to finish in spring 2015.
15. Potala Palace, Tibet
Thirteen stories, white walls measuring over 3 metres wide, more than 1000 rooms and countless shrines and statues combine to produce the massive, unconquerable Potala Palace in eastern Tibet. The Dalai Lama lived here until the 1959 Tibetan uprising, and it’s now a well-visited museum.
The coastal town of Kotor is encircled by a extensive walled fortification system that has had to contend with Ottoman sieges, Venetian and Habsburg rule, Russian occupation and vicious British attack – not to mention a handful of destructive earthquakes, which put it on the World Heritage List of Danger until 2003.
17. Malbork Castle, Poland
An unfathomable number of red bricks went into the making of Poland’s Malbork Castle. A classic medieval fortress founded by the Teutonic Knights, complete with moats, towers and ramparts, the castle was pulverised during World War II. Today, visitors can see the result of admirable and ongoing restoration.
18. Buda Castle, Hungary
Commanding the River Danube and the higgledy-piggledy Castle District around it, Budapest’s fortress was the glitzy, golden home of the Hungarian kings, dubbed, unsurprisingly, the Royal Palace. It’s a rather plain beast today compared to what it once was and instead of regal folk, now houses museums and galleries.
19. Krak de Chevaliers, Syria
Built strategically on top of a hill east of Taurus, eastern Syria, the magnificent Krak de Chevaliers was originally a Crusader castle, constructed in the twelfth century (though the site was inhabited before that). T. E Lawrence once described it as “perhaps the best preserved and most wholly admirable castle in the world” and today it still has remnants of medieval frescoes within.
20. Conwy Castle, Wales
Eight massive towers and a vast, thick curtain wall protect Conwy’s castle with extraordinary medieval might. The fortress dates from the reign of Edward I and his Conquest of Wales, and it has been centre stage during many consecutive bloody battles, before enjoying a decidedly more peaceful role as the subject of Victorian paintings and tourist rambles.