Located in Jodhpur, India, Mehrangarh Fort played the role of the prison that holds Batman in the 2012 action film “The Dark Knight Rises.” According to the film’s lore, Ra’s al Ghul’s son was the only prisoner to ever survive an escape attempt, until Batman does the same. Mehrangarh Fort was built in 1460 by Rao Jodha, founder of the city of Jodhpur.

Located on Pea Patch Island in the Delaware River, Fort Delaware served as a major prison of Confederate soldiers during the Civil War. More than 33,500 Confederate soldiers were at one time detained within the fort, which was surrounded by a 12-foot deep, 30-foot wide moat. The fort now encompasses a living history museum.

Built in 1115 by King Baldwin I of Jerusalem, Montreal is a crusader castle in modern-day Jordan, part of a group of structures built in the Eastern Mediterranean and Middle East during the Crusades. The crusaders called it Mons Regalis or Montreal, which translated to Royal’s Castle or King’s Castle. It held a strategically important place along the route from Syria to Arabia.

You’re probably familiar with the Great Wall of China, but did you know that there is also a Great Wall of India? The world’s second longest continuous wall after China’s, Kumbhalgarh Wall extends for 22 miles around Kumbhalgarh Fort in northwest India, sandwiched between two peaks in the Aravalli mountain range. Kumbhalgarh measures nearly 50 feet across at its widest section and dates back to the fort’s 16th-century construction.

The Cheyenne Mountain Complex was built in the 1960s and once served as headquarters of NORAD (North American Aerospace Defense Command) and the United States Space Command. The fortress is built into a mountain in El Paso County, Colorado, and its 15 subterranean facilities are both earthquake and explosion proof.

Built in 1323, the Oreshek (or Shlisselburg) Fortress is located on an island where Lake Ladoga flows into the Neva River, near present-day St. Petersburg. The fortress was built to defend Veliky Novgorod, one of Russia’s oldest cities. It was later used as a political prison and was officially abandoned following the 1917 Russian Revolution. Oreshek is now a museum and part of a UNESCO World Heritage Site.

Located 70 miles west of Key West, Florida, Dry Tortugas National Park is accessible only by boat or seaplane. The park is home to Fort Jefferson, the largest brick structure in the Western Hemisphere, made of some 16 million bricks. The fort was originally built to provide military protection to ships heading to the Florida coastline, though it also served as a prison during the Civil War.

Towering above the city of Granada, Spain, is the stunning Alhambra, which means “Red Castle” in Arabic. Named for its red-colored walls, the fortress was built strategically to overlook the city in the 9th century. Mohammed ben Al-Hamar (Mohammed I) ordered a royal residence constructed within the fortress during the 13th century.

Rumeli Castle was built in four months in 1452, under the orders of Ottoman Sultan Mehmed II (aka Mehmed the Conqueror) prior to the conquest of what was then called Constantinople. The fortress functioned as a defense against attacks from the north of the Bosphorus Strait. After a 53-day siege, the city became the capital of the Ottoman Empire and was renamed Istanbul.

Constructed in 1593 and originally surrounded by a swampy moat, the star-shaped Fort Bourtange helped the Dutch fight the Spaniards in the Eighty Years’ War. Fort Bourtange remained useful for centuries, although the swamp dried up by the mid-1800s and the fort eventually transitioned into a residential town. The local government declared it an open-air historical area by 1960.

The largest brick fortress in the world is found on the banks of the Nogat River in Poland. Malbork Castle was built entirely out of brick by Teutonic Knights in the 13th century, with three castles sprawling across 52 acres surrounded by three rings of defensive walls and a large moat. It was named a UNESCO World Heritage site in 1997.

After the Norman Conquest of England, King William I (aka William the Conqueror) built a massive stone fortress in 1066, which is now known as the Tower of London. Built to protect William’s power and intimidate his foes, the fortress was also used as a prison and is the home of the Royal Mint and the Crown Jewels of England.

Built in 1638 under Mughal Emperor Shah Jahan, the Red Fort, or Lal Qila, was the seat of the Mughal empire for 200 years. To celebrate independence from the United Kingdom, the Indian flag is flown above the fortress on Independence Day as the prime minister gives his address there.

On December 20, 1860, South Carolina became the first state to secede from the Union, and on April 12, 1861, Confederate forces attacked Union forces at South Carolina’s Fort Sumter, officially beginning the Civil War. Today, the fort — located in the middle of Charleston Harbor and accessible only by ferry — is open to the public for tours, along with nearby Fort Moultrie.

The Louvre was originally built in 1190 for a very different purpose: as a fortress to protect the city of Paris. As the city grew around it, the location of the fortress was no longer strategic for defense, so in the 16th century it was reconstructed to serve as a royal palace. After the royal residence moved to Versailles in 1682, the Louvre opened as a public art museum in 1793.

The Citadel of Aleppo is a castle fort in Aleppo, Syria, one of the world’s oldest continuously inhabited cities. Use of the castle dates back to 3000 BCE, but much of the current structure was likely built during the Ayyubid dynasty in the 12th century. The fortress has weathered centuries of ups and downs (including significant damage in the ongoing Syrian Civil War) but remains standing to this day.

Long before it was a military fort, the Alamo was the chapel of a Roman Catholic mission. Franciscan missionaries laid the foundation stone for the first permanent building at the site in 1744. After it collapsed in 1756, construction began but never finished on a second chapel that was later handed over to local authorities. By 1805, the site was being used as a fort to treat Spanish soldiers who had been injured on the frontier.

One of the oldest fortified military sites in North America, Fort Independence was built in the 1600s on Castle Island, with a strategic location overlooking Boston Harbor. The structure was previously called Castle William after William II of England; President John Adams renamed it Fort Independence in 1799. Today it is part of the Boston National Historical Park.

Before it was set to music and named the national anthem, “The Star-Spangled Banner” began as a poem titled “Defence of Fort M’Henry,” written by lawyer Francis Scott Key. The poem was composed after a battle at the fort during the War of 1812. In 1925, the fort, which sits on Baltimore Harbor, became a National Monument, and it is now open to the public.

Holding over 147.3 million ounces of gold, Kentucky’s Fort Knox is home to roughly half of all gold possessed by the U.S. Treasury. The next largest American gold reserves are found in West Point, New York (54.1 million ounces) and in Denver, Colorado (43.9 million ounces). The gold is held as an asset by the U.S. Treasury at $42.22 an ounce, worth over $6.2 billion today.