While many defensive castles have fallen into disrepair over the centuries (though that’s often part of their charm), England’s Windsor Castle remains grand—inside and out—likely because it’s been home to 40 monarchs, including King Charles III. There’s a huge amount to see here, too, from the gilded Ceremonial Rooms to the Changing of the Guard ceremony. Windsor is also near London, making it an easy and popular day trip from the capital.

The town of Carcassonne in Southern France is home to the UNESCO World Heritage–listed Carcassonne Castle (Cité de Carcassonne), a majestic turreted château that’s almost 900 years old. It stands on a hill in the middle of town and this isn’t just so it looks attractive from below—the castle was a fortified defense and saw a lot of action in its early centuries, thanks to its strategic location between the rival kingdoms of France and Aragon.

Rome’s Castel Sant’Angelo is an imposing circular building that contains the graves of Roman Emperor Hadrian and other later emperors. It was built in the 2nd century, making it only slightly younger than the Colosseum, but was converted into the fort you can see today in the 5th century (so, it’s still way older than most modern nations). Today, you can go inside to admire the collection of art, archaeological finds, and weaponry of the Castel Sant'Angelo National Museum.

Wales is nicknamed the Land of Castles because, with more than 600 in the small country, it has more castles than anywhere else in the world. If you don’t have time to visit all 600, plan to stop at Caenarfon Castell (Carnarvon Castle). The late-13th-century polygonal fort–palace is generally considered one of the greatest medieval buildings in the world and a must-stop on any adventure through North Wales.

Atop Hdracany Hill overlooking the city, Prague Castle (Prazský hrad) doesn’t immediately strike most people as a “castle” in the traditional sense. The Prague Castle complex is actually a collection of palaces, museums, churches, and gardens within walls, with St. Vitus Cathedral at its center. The oldest parts date from the 9th century but as the castle includes Romanesque, Gothic, Renaissance, baroque and other structures, there’s a lot to see here.

While Germany’s Neuschwanstein Castle is one of the most famous castles around the world, it’s relatively young, having been built in the late 19th century. In contrast, the ruins of 13th-century Heidelberg Castle reflects centuries of European conflict, and is arguably the more interesting pick—as well as being beautiful. Unfortunately, the castle was destroyed by the French in the late 17th century, so it didn’t just fall into ruin through neglect, but it's still worth visiting.

Located on Egypt’s Mediterranean Sea coast, the 15th-century Citadel of Qaitbay in Alexandria is practically a baby compared to other tourist attractions such as the Giza Pyramids or the Valley of the Kings. But it was once one of the most important defenses in the Mediterranean, and it does have a link to antiquity: it was built over the site of the Lighthouse of Alexandria, one of the Seven Wonders of the Ancient World. Nowadays, you’ll find a small museum and wonderful coastal views there.

Jaisalmer Fort is definitely one of the most magical castles around the world. The city of Jaisalmer in the Indian state of Rajasthan is the stuff of desert dreams, and at its center is the 12th-century Jaisalmer Fort. It looks like the kind of sandcastle you might have made at the beach as a child, but luckily it’s built of sturdier stuff—some 4,000 people still live within the fort’s walls. Inside, you can explore museums and havelis (mansions), dine, and shop for local crafts.

While many of Japan’s traditional feudal castles were destroyed in World War II bombings, the beautiful Himeji Castle (Himeji-jo)—which dates from the early 17th century—is an unreconstructed original. It’s often named Shirasagi-jo in Japanese, which translates as White Heron Castle, because of its color and its elegance, and is certainly one of the most picturesque castles worldwide.

The UNESCO World Heritage–listed Potala Palace was the winter palace of the Dalai Lamas from the 7th century until 1959, when the current Dalai Lama fled China. The magnificent fortress is still the spiritual heart of Tibetan Buddhism, though, and these days, you can visit the Potala Palace on a guided tour to see the Tibetan Buddhist art and artifacts inside.

Nothing says Silk Road splendor quite like Uzbekistan’s Itchan Kala Fortress in Khiva. The fortified city houses hundreds of homes and around 50 historic monuments reflecting various stages of Islamic architecture. The blue, turquoise, and white mosaic detailing on the domes, turrets, and minarets are one highlight of Itchan Kala; the 30-foot (9-meter) high, 1.5-mile (2.5-kilometer) long wall that stretches around its perimeter is another.

While many of the most beautiful castles in the world are located in the “old world” of Europe and Asia, the “new world” of the Americas also gets a look in. Puerto Rico’s Castillo San Felipe del Morro was built in the 16th century, making it just as old as many European castles. It was built to defend the entrance to San Juan Bay, and its location is what makes it so beautiful, with the fortress and cliffs dropping into the ocean below.