Corryvreckan whirlpool: Scotland's 'raging cauldron' that is named after a Norse king and said to house a witch

The Corryvreckan whirlpool is a fierce, circular current between the Scottish isles of Jura and Scarba. Nicknamed the "raging cauldron," it almost killed George Orwell and his son Richard in 1947.

The whirlpool is named after the Gulf of Corryvreckan, which, according to tradition, is named after the Norse king Breckan. Legend has it that Breckan anchored his boat in the whirlpool for three days to prove his valor to a Scottish chief whose daughter he wanted to marry. The Norse king used three ropes to anchor his vessel — one woven from hemp, another from wool, and a third from the hair of virgins — but they snapped, drowning him. According to the legend, the virgins' hair should have kept Breckan safe, but one of the women had been unchaste.

"Corry" in "Corryvreckan" is derived from the Gaelic word for cauldron "coire," so the full name means "the cauldron of Breckan."

Related: Drake Passage: The 'most dreaded bit of ocean on the globe' — where waves reach up to 80 feet

The Corryvreckan whirlpool is one of the largest whirlpools in the world. (Others include Saltstraumen in Norway, Old Sow in Canada, and Naruto in Japan.)

The whirlpool is caused by ocean currents that skirt the east and west coasts of Jura before meeting off the island's northernmost tip, in the Gulf of Corryvreckan. The gulf acts like a funnel, forcing waters into the narrow strait between Jura and Scarba and increasing their speed to 8.5 knots (10 mph or 16 km/h), according to the Universities Space Research Association (USRA).

A huge hole in the gulf's eastern end and an underwater basalt-rock pillar directly off Scarba then create a swirling motion by pushing water down and then up. The hole is 720 feet (220 meters) deep, according to the USRA. The pillar — known as the "Old Hag" due to folkloric tales of a witch living there — rises from a depth of 230 feet below the surface to 95 feet below the surface (70 to 29 m).

The whirlpool, located above the Old Hag, is sometimes so strong that its roar can be heard 10 miles (16 km) away, according to BBC Glasgow and West Scotland. Waves can reach up to 30 feet (9 m) high, making the Gulf of Corryvreckan one of the most dangerous passages around the British Isles.

Indeed, Orwell and his son nearly drowned during a boat trip around Jura in 1947. They were living on the island while Orwell wrote his famous novel "1984" and wouldn't have made it back if fishers hadn't saved them from the whirlpool, according to the BBC.

Discover more incredible places, where we highlight the fantastic history and science behind some of the most dramatic landscapes on Earth.