10 Things You Didn't Know About Edinburgh Castle

Edinburgh Castle, one of Scotland's most recognizable buildings, has stood tall above the city's spectacular terrain from time immemorial. With a record-breaking 1.7 million visitors this year, the castle's storied history is on display for all to see—or is it? From ghostly occupants to its Cold War history, here are ten things you may not have known about this legendary fortification.

The castle lies above a volcano.

But don't worry, the volcanic explosion that built Castle Rock erupted approximately 340 million years ago. Archaeological evidence reveals that humans have lived on Castle Rock since 850 BC. However, when it came time to build the Edinburgh Castle we know and love on the mound in the 12th century, they did it directly above the plug of the volcanic vent. The architects must have been convinced that the volcano wouldn't erupt again, right?

It is the most besieged place in Great Britain.

Edinburgh Castle has been attacked 23 times, making it Europe's most heavily fortified stronghold. Notable examples include the Longshanks Siege in 1296, when Edward I raided the castle and transported all of its wealth to London. There's also the Lang Siege, which lasted from 1571 to 1573, after the castle's garrison declared its support for Mary, Queen of Scots. The last siege occurred during the 1745 Jacobite Rising, when Bonny Prince Charlie attempted and failed to conquer the citadel. Aside from the regular influx of tourists, the castle has had a tranquil existence since.

St. Margaret’s Chapel is the oldest building in Scotland.

Because of Edinburgh Castle's turbulent past, the many buildings that comprise the site come from different periods in Scottish history. St. Margaret's Chapel, built in the 12th century, is by far the oldest. She was named after Queen Margaret, the consort of Malcolm III of Scotland, and died only three days after learning of King Malcolm's death in battle. When Robert the Bruce took the castle in 1314, he saved only one structure from destruction.

The Scottish crown jewels were lost in the castle for many years.

The Crown, Sceptre, and Sword of State are collectively referred to as the Honours of Scotland. These were used in the crowning of Scottish monarchs and are the only pieces of British regalia that survived Oliver Cromwell's purging of royal insignia. However, following the Union of 1707, which united Scotland and England under one crown, the Honours were sealed in a chest in Edinburgh Castle and forgotten for over a century, until Sir Walter Scott found them in 1818. They've been on permanent exhibit in the castle ever then, with the exception of World War II, when they were hidden again in fear of falling into German hands.

The ghost of Lone Piper haunts the castle.

According to legend, underground passageways running beneath the castle were found hundreds of years ago, connecting various districts of Edinburgh. A young piper was sent into the tunnels and told to play his pipes as he moved, so that those above might figure out where the subterranean channels led. However, his music unexpectedly ceased, and when they searched the tunnels for him, they discovered no trace of the young piper. According to legend, his ghostly piping may still be heard beneath the castle, awaiting rescue.

There's a cannon that has kept time since 1861.

In the days before iPhones and Rolexes, sailors on ships traveling through the Firth of Forth would keep their ears open for an unmistakable booming noise coming from Edinburgh Castle at the same time each day. The shot fired by the original 18-pound gun could be heard for miles, allowing the sailors to adjust and reset their chronometers to the correct time. Though its timekeeping duties are no longer required, a gun is nonetheless fired from the castle's battery on a daily basis as a popular tradition.

The castle once housed an elephant.

We're not trying to pull your trunk; in 1838, the 78th Highlanders returned to Edinburgh from a protracted deployment in Sri Lanka with a full-grown elephant. Because the castle was one of the principal infantry barracks, the elephant stayed there with his soldiers and was the leader of their marching band. He reportedly developed a taste for beer and is said to have slipped his trunk through the canteen window for a pint before bed. His toes are currently on display in the National War Museum on the castle grounds.

The KGB altered the castle.

As the saying goes, walls are like ears. In the 16th century, a paranoid King James IV of Scotland had small holes drilled into the Great Hall of Edinburgh Castle to spy on his courtiers' conversations. These holes, known as the 'laird's lugs' or the lord's ears, remained a public secret until Soviet President Mikhail Gorbachev's planned visit to Edinburgh in 1984. Before he arrived in Scotland, the KGB requested that the holes be bricked over in preparation for his visit to the castle. Espionage never gets old.

It has imprisoned nearly 1,000 convicts in its history.

Aside from royalty, the castle hosted some very infamous tenants, including 21 pirates from the Caribbean who were eventually sentenced to death by hanging. During the War of Independence, Edinburgh Castle imprisoned a number of Americans; in fact, one prisoner defiantly carved the American flag into the walls of the castle's vaults while incarcerated, which is today thought to be the oldest portrayal of the Stars and Stripes in history.

There is a dog cemetery on the grounds of the castle.

A little patch of ground off the main approach to Edinburgh Castle has been devoted to the canine companions of Scottish battalions since 1840. From Jess, the beloved mascot of the Black Watch 42nd Highlanders, to Dobbler, who accompanied the Argyll and Sutherland Highlanders from China to Sri Lanka and South Africa, these pooches are honored for their loyalty and service by being buried on castle grounds, a tradition typically reserved for nobility and distinguished soldiers. Visitors are not allowed to enter the cemetery, however the garden may be seen from the Argyle Battery above.