Hidden Secrets of Famous Landmarks: 50 Fascinating Facts

Peter's Basilica in Vatican City, one of the most important Catholic churches in the world, was funded by selling indulgences—letters excusing you from sin. Rich people even bought these in advance for sins they planned on committing. During the demolition of Old St. Peter's Basilica in the Vatican in the 17th century, over 100 papal tombs were destroyed.

When the Hoover Dam was being drafted, engineers calculated that it would take 125 years for the concrete to cool if done in a single pour. Instead, they poured it in sectioned blocks, some as big as 50 square feet and 5 feet high. This way, the physical dam itself will survive up to 10,000 years and be one of the last remaining visible and recognizable monuments of humans on the planet. Also, the first death occurred on December 20, 1922, during its construction. Exactly 13 years later, on December 20th, 1935, the last death occurred, and the two men were father and son, respectively.

Petra in Jordan had a more efficient and advanced water system than ancient Rome, with a sophisticated water management system that allowed its 40,000 inhabitants to survive in the harsh desert environment. Scientists have discovered a hidden monument in the center of Petra using high-resolution satellite images, drone photos, and ground surveys, and they estimate there are still many undiscovered tombs and ruins buried beneath the ground. Despite extensive archaeological excavations and research, only about 15% of the ancient city has been fully explored and documented.

There is a "secret" entrance to the Louvre that allows you to bypass the ridiculous line at the public entrance. The Porte des Lions entrance is the best entrance into the Louvre. From this entrance, you can buy your tickets, enter the museum, and have the shortest route to the Italian Renaissance painting section. This door always has the shortest line. Also, if you wanted to see every piece of art in The Louvre in one visit, it would take you over a month, assuming you were there 24/7 and took no breaks or sleep.

"Kremlin" means "fortress inside a city," and there are multiple kremlins in Russia. "The Kremlin," which is popularly known, refers to the Moscow Kremlin, which includes five palaces, four cathedrals, and the defensive walls and towers. Supposedly, the whole of Moscow has a secret underground metro system that parallels the public Moscow metro, which connects the Kremlin to the FSB headquarters as well as other locations of national importance. Additionally, some of the Soviet Union's honored dead were buried inside the Kremlin wall.

The Parthenon in Athens has stood largely intact for more than 2000 years, but the ruins we see today are the result of a massive explosion in 1687, not natural forces or the passage of time. During a war between Venice and the Turks, the Venetians hit the building with a mortar round, causing the explosion. The Turks were using the building to store gunpowder, and it is said they didn't expect such a historic monument to be targeted. Tragically, the blast killed 300 people. Originally built as a temple for the goddess Athena, the Parthenon has served as a church and mosque throughout its history.

The Tower of Hercules, located in A Coruña, Galicia, Spain, is the oldest extant lighthouse in the world and is still in use today. Built between the 1st and 2nd centuries A.D., it was modeled after the Lighthouse of Alexandria.

Edinburgh Castle in Scotland was built on top of a volcano and is so old that its founding was already shrouded in myth and legend by the time of its first definite mention in literature. The infamous "Red Wedding" scene from "A Storm of Swords" by G.R.R. Martin was inspired by real-life events that occurred at Edinburgh Castle in 15th century Scotland, known as "The Black Dinner". Additionally, the castle has a secret underground tunnel leading to nearby Holyrood Palace, which was rediscovered during a renovation project in the 1990s and is now open to the public for guided tours.

The Chichen Itza in Mexico, constructed to honor the Mayan deity Kukulan, the Feathered Serpent, is renowned for its impressive feats. On the spring and autumn equinoxes, it creates the shadow of a snake slithering down the pyramid. Interestingly, the pyramid has steps of different heights on each of its four sides: 92, 91, 91, and 91, which add up to 365. Additionally, if you clap your hands in front of the pyramid, its echo will sound like a chirping bird.

The builders of the Empire State Building were determined to make it the tallest building in the world in 1931 and not the Chrysler Building, even going so far as to add a 222-foot (68 m) mooring mast on top of it for zeppelins to dock. In 1945, an airplane crashed into the building, causing significant damage, including severing the cables of an elevator. Despite falling over 70 stories, the woman inside the elevator survived and holds the world record for the longest-survived elevator fall. Interestingly, the Empire State Building's observation deck generates more revenue than all the commercial tenants in the remaining 101 floors combined.