Wherever there is money, there will be castles built. I found 300 castles in the United States alone! But it’s the older castles with a rich history that I want to visit. You know about Buckingham Palace, the Vatican Palace, and the Forbidden City, and here are some other fascinating castles you may not be familiar with.

1. Predjamski

Predjamski Castle in Slovenia is built into the entrance of a cave system that runs through the mountain, making it a seige-proof fortress. It was first constructed in the 13th century, and expanded several times. Predjamski Castle has its own railway and concert hall! You can see panoramic photos of the castle interior, the cave under the castle, and more pictures here.

2. Mont Saint-Michel

Mont Saint-Michel was built on a tiny tidal island just off the French coast in the 8th century as a monastery. It was greatly expanded in the 11th and 12th centuries, then converted to a prison after the French Revolution. The prison closed in 1963. Mont Saint-Michel has been featured in numerous movies, cartoons, and even videogames. See more photos here.

3. Castel Gandolfo

Castel Gandolfo lies at the intersection of religion and science. Actually, it is located on a ridge outside Rome. Built in the 17th century over the ruins of a Roman palace, it is the Pope’s summer residence, but also the home of the Vatican Observatory. Of the three domes you see, one is a church, the other two are mobile telescope domes!

More fascinating castles, after the jump.

4. Palacia de Pena

Palacia de Pena (Pena Palace) is perched atop the Sintra mountain range in Portugal. First built in the 15th century as a palace, it was later reconstructed and donated to the church as a monastery. An earthquake in 1755 ruined most of it. Prince Fernando aquired it in 1838 and rebuilt and expanded it. The style of the palace is a eclectic combination of the original and subsequent styles, plus Romantic, Bavarian, and Moorish architecture, plus an English garden.

5. Taktshang

Taktshang (Tiger’s Nest Monastery) in Bhutan hangs on the side of a cliff 2,300 feet above the Paro valley. The mountain houses nine sacred caves. The constucrtion of the original Buddhist temple began in 1692, and was recently restored after a devastating fire in 1998. Access to Taktshang is by foot or by mule only. Save yourself some steps and see a huge gallery of photos here.

6. St. Hilarion

St. Hilarion Castle in North Cyprus was built on the site where the monk who would become St. Hilarion lived his hermit’s life in a cave. The Byzantines built monastery and church in the tenth century, and expanded into a castle in the 12th century, used as a watchtower and defense against Arab pirates. It was decommisioned in the 15th century to save money, and fell into ruins.

7. Chillingham

Chillingham Castle is in Northumberland, near the England-Scotland border. Originally built in the 12th century as a monastery, it became a military stronghold in the medieval battles between the two nations. The current owners claim that it is the most haunted castle in Britain, with sporadic appearances by the “blue boy,” Lady Mary Berkeley, and other ghosts.

8. Bran

Earlier this year, we all saw the news that Dracula’s Castle was up for sale. This is Bran Castle near Brasov, in the Transylvania region of Romania. Historians don’t think Vlad the Impaler ever lived there. According to some accounts, he spent a couple of days in the dungeon of Bran Castle as the guest of the Ottoman Empire. However, Bran Castle inspired Bram Stoker’s writings, and it was also used in some Dracula films.

9. Poienari

Vlad Tepes actually lived at Poienari Castle in the Wallachia region of Romania. High on the side of a mountain, it was a imposing military fortress. Poienari was abandoned in the 16th century. A landslide in 1888 brought down some of the walls. To see the ruins of Poienari Castle, you must climb 1,426 steps, or just click here.