1. The Kingdom of Prester John

For more than 500 years, Europeans believed a Christian king ruled over a vast empire somewhere in the wilds of Africa, India or the Far East. The myth first gained popularity in 1165, after the Byzantine and Holy Roman emperors received a letter—most likely a European forgery—from a monarch calling himself “Prester John.” The mysterious king claimed to serve as “supreme ruler of the three Indies” and all its 72 kingdoms. He described his realm as a utopia rich in gold, filled with milk and honey and populated by exotic races of giants and horned men. Perhaps most important of all, Prester John and his subjects were Christians—even the name “Prester” meant “Priest.”

A Papal mission to find Prester John’s court disappeared without a trace, but the myth of his kingdom took hold among Europeans. Crusading Christians rejoiced in the idea that a devout ruler might come to their aid in the struggle against Islam, and when Genghis Khan’s Mongol hordes conquered parts of Persia in the early 1200s, many mistakenly credited Prester John’s forces with the attack. The fantastical kingdom later became a subject of fascination for travelers and explorers. Marco Polo spun a dubious tale about encountering its remnants in Northern China, and Vasco da Gama and other Portuguese mariners quested after it in Africa and India. While explorers did eventually discover a far-flung Christian civilization in Ethiopia, it lacked the grandeur—and the gold—that Europeans had come to associate with Prester John’s realm. By the 17th century, the legend had faded, and the famed empire was dropped from most maps.

2. Hy-Brasil

Long before Europeans ever stepped foot in the Americas, explorers searched in vain for the island of Hy-Brasil, a spectral atoll said to lurk off the west coast of Ireland. The story of the island most likely comes from Celtic legend—its name means “Isle of the Blest” in Gaelic”—but its precise origins are unclear. Hy-Brasil first started appearing on maps in the 14th century, usually in the form of a small, circular island narrowly split in two by a strait. Many mariners accepted it as a real place until as recently as the 1800s, and it became popular fodder for myths and folktales. Some legends described the island as a lost paradise or utopia; others noted that it was perpetually obscured by a dense curtain of mist and fog, and only became visible to the naked eye every seven years.

Despite its fanciful reputation, Hy-Brasil was widely sought after by Britain-based explorers in the 15th century. The navigator John Cabot launched several expeditions to track it down, and supposedly hoped to encounter it during his famous journey to the coast of Newfoundland in 1497. Documents from Cabot’s time claim that previous explorers had already reached Hy-Brasil, leading some researchers to argue that these mariners may have inadvertently traveled all the way to the Americas before Christopher Columbus.

3. Thule

A subject of fascination for ancient explorers, romantic poets and Nazi occultists alike, Thule was an elusive territory supposedly located in the frozen North Atlantic near Scandinavia. Its legend dates back to the 4th century B.C. when the Greek journeyman Pytheas claimed to have traveled to an icy island beyond Scotland where the sun rarely sets and land, sea and air commingled into a bewildering, jelly-like mass.

Many of Pytheas’ contemporaries doubted his claims, but “distant Thule” lingered in the European imagination, and it eventually came to represent the northernmost place in the known world. Explorers and researchers variously identified it as Norway, Iceland and the Shetland Islands, and it served a recurring motif in poetry and myth. The island is perhaps most famous for its connection to the Thule Society, a post-World War I esoteric organization in Germany that considered Thule the ancestral home of the Aryan race. The Munich-based group counted many future Nazis among its guests, including Rudolf Hess, who later served as Deputy Führer of Germany under Adolf Hitler.

4. El Dorado

Beginning in the 16th century, European explorers and conquistadors were bewitched by tales of a mythical city of gold located in the unexplored reaches of South America. The city had its origin in accounts of “El Dorado” (“The Gilded One”), a native king who powdered his body with gold dust and tossed jewels and gold into a sacred lake as part of a coronation rite. Stories of the gilded king eventually led to rumors of a golden city of untold wealth and splendor, and adventurers spent many years—and countless lives—in a fruitless search for its riches.

One of the most famous El Dorado expeditions came in 1617 when the English explorer Sir Walter Raleigh traveled up the Orinoco River on a quest to find it in what is now Venezuela. The mission found no trace of the gilded city, and King James I later executed Raleigh after he disobeyed an order to avoid fighting with the Spanish. El Dorado continued to drive exploration and colonial violence until the early 1800s when the scientists Alexander von Humboldt and Aimé Bonpland branded the city a myth after undertaking a research expedition to Latin America.

5. St. Brendan’s Island

St. Brendan’s Island was a mysterious incarnation of Paradise once thought to be hidden somewhere in the eastern Atlantic Ocean. The myth of the phantom isle dates back to the “Navigatio Brendani,” or “Voyage of Brendan,” a 1,200-year-old Irish legend about the seafaring monk St. Brendan the Navigator. As the story goes, Brendan led a crew of pious sailors on a 6th-century voyage in search of the famed “Promised Land of the Saints.” After a particularly eventful journey on the open sea—the tale describes attacks by fireball-wielding giants and run-ins with talking birds—Brendan and his men landed on a mist-covered island filled with delicious fruit and sparkling gems. The grateful crew is said to have spent 40 days exploring the island before returning to Ireland.

While there is no historical proof of St. Brendan’s voyage, the legend became so popular during the medieval era that “St. Brendan’s Island” found its way onto many maps of the Atlantic. Early cartographers placed it near Ireland, but in later years it migrated to the coasts of North Africa, the Canary Islands and finally the Azores. Sailors often claimed to have caught fleeting glimpses of the isle during the Age of Discovery, and it’s likely that even Christopher Columbus believed in its existence. Nevertheless, its legend eventually faded after multiple search expeditions failed to track it down. By the 18th century, the famed “Promised Land of the Saints” had been excised from most navigational charts.

6. The Kingdom of Saguenay

Explorer Jacques Cartier
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Explorer Jacques Cartier

The story of the mirage-like Kingdom of Saguenay dates to the 1530s, when the French explorer Jacques Cartier made his second journey to Canada in search of gold and a northwest passage to Asia. As his expedition traveled along the St. Lawrence River in modern-day Quebec, Cartier’s Iroquois guides began to whisper tales of “Saguenay,” a vast kingdom that lay to the north. According to a chief named Donnacona, the mysterious realm was rich in spices, furs and precious metals, and was populated by blond, bearded men with pale skin. The stories eventually drifted into the realm of the absurd—the natives claimed the region was also home to races of one-legged people and whole tribes “possessing no anus”—but Cartier became taken by the prospect of finding Saguenay and plundering its riches. He brought Donnacona back to France, where the Iroquois chief continued to spread tales of a lost kingdom.

Legends about Saguenay would haunt French explorers in North America for several years, but treasure hunters never found any trace of the mythical land of plenty or its white inhabitants. Most historians now dismiss it as a myth or tall tale, but some argue the natives may have actually been referring to copper deposits in the northwest. Still, others have suggested that the Indians’ Kingdom of Saguenay could have been inspired by a centuries-old Norse outpost left over from Viking voyages to North America.