A lot of the allure of these places comes from the history and human drama that played out within their walls, as well as the astonishing architecture that features on so many castles. They're also romantic and somewhat mystical, places that spark our imagination and conjure visions of knights in shining armor and powerful queens.

"Because they combine two functions, they are far more interesting than fortresses or palaces," Marc Morris, the author of 'Castles: Their History and Evolution in Medieval Britain' told CNN Travel.

"What makes a castle a castle is that it combines the functions of defense and dwelling — it's a fortification and a stately home rolled into one," Morris said.

The author highlighted that creating a building which is both comfortable and defensible is difficult. "The ingenious ways in which castle-designers reconciled this balance is always intriguing."

Even though we normally associate castles with European history, as you can see from this list, it's actually an architectural form found around the globe — in nations as varied as Japan and India, Morocco and Mexico.

Many are now hubs of living history where modern visitors can watch jousting and other ancient combat forms, listen to medieval music or watch artisans demonstrate the arts, crafts and everyday skills of a century from years ago.

They also make great backdrops for outdoor events, such as concerts, films, plays and military performances, or for the on-location filming of movies and television shows.

"With a castle, you get not only the stories of sieges, but also stories of the domestic lives of the rich and famous," Morris said.

"Castles are places where plots were hatched, marriages were consummated, murders carried out, royal babies born, and so on. With castles, you are never short of fascinating things to talk about," Morris added.

Maybe that's why after all these years they still excite even children. For example, Lego just revealed a new set at LegoCon 2022 called The Lion Knights' Castle, which takes inspiration from the 1970s Yellow and Black Knight's castles. However, something tells me quite a few adults will be playing with them too.

Whether you want battlements or baronial glamor, it's also possible to stay in the U.K.'s oldest buildings. 

Some are part of organizations such as the National Trust, the Landmark Trust, or English Heritage while private owners tend to use Loyd & Townsend Rose.

Staying in one of L&TR properties allows you to soak up history in a way that's not possible on a day trip. Its extensive portfolio includes such beauties as the Inveraray Castle on the banks of Loch Fyne.