The Rupes Nigra a phantom island

Phantom island

Phantom islands are islands that were believed to exist, and appeared on maps for a period of time during recorded history, but were later removed after they were proved to be nonexistent...

, was believed to be a 33-mile-wide magnetic island of black rock located at the Magnetic North Pole or at the North Pole

North Pole

The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is, subject to the caveats explained below, defined as the point in the northern hemisphere where the Earth's axis of rotation meets its surface...

 itself. It purportedly explained why all compasses point to this location. The idea came from a lost work titled Inventio Fortunata

Inventio Fortunata

Inventio Fortunata , "Fortunate, or fortune-making, discovery", is a lost book, probably dating from the 14th century, containing a description of the North Pole as a magnetic island surrounded by a giant whirlpool and four continents...

, and the island features on maps from the sixteenth and seventeenth centuries, including those of Gerardus Mercator

Gerardus Mercator

thumb|right|200px|Gerardus MercatorGerardus Mercator was a cartographer, born in Rupelmonde in the Hapsburg County of Flanders, part of the Holy Roman Empire. He is remembered for the Mercator projection world map, which is named after him...

 and his successors. Mercator describes the island in a 1577 letter to John Dee

John Dee

John Dee was a Welsh mathematician, astronomer, astrologer, occultist, navigator, imperialist, and consultant to Queen Elizabeth I.John Dee may also refer to:* John Dee , Basketball coach...

:

In the midst of the four countries is a Whirl-pool, into which there empty these four indrawing Seas which divide the North. And the water rushes round and descends into the Earth just as if one were pouring it through a filter funnel. It is four degrees wide on every side of the Pole, that is to say eight degrees altogether. Except that right under the Pole there lies a bare Rock in the midst of the Sea. Its circumference is almost 33 French miles, and it is all of magnetic Stone (…) This is word for word everything that I copied out of this author [Jacobus Cnoyen] years ago.

In fiction

In Jules Verne

Jules Verne

Jules Gabriel Verne was a French author who pioneered the science fiction genre. He is best known for his novels Twenty Thousand Leagues Under the Sea , A Journey to the Center of the Earth , and Around the World in Eighty Days...

's The Adventures of Captain Hatteras (1866), the North Pole

North Pole

The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is, subject to the caveats explained below, defined as the point in the northern hemisphere where the Earth's axis of rotation meets its surface...

 is occupied by Queen Island, created by a volcano

Volcano

2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

 (Mount Hatteras) in the middle of an Open Polar Sea

Open Polar Sea

The Open Polar Sea was a hypothesized ice-free ocean surrounding the North Pole. This unproven theory was once so widely believed that many exploring expeditions used it as justification for attempts to reach the North Pole by sea, or to find a navigable sea route between Europe and the Pacific...

.