Maps aren’t always as accurate as we’d like to believe.

Just ask British author Edward Brooke-Hitching, who details 70 of the most epic fails in his new book The Phantom Atlas: The Greatest Myths, Lies And Blunders On Maps.

It’s “an atlas of the world not as it ever existed, but as it was thought to be,” says the London-based writer ― who researched ghost islands, non-existent mountain ranges, hoax golden cities and fake continents for the tome.

“All of them at one time or another were absolutely believed, sometimes for centuries, to be real because they were drawn on maps,” the 33-year-old told The Huffington Post.

“Maps have an unquestionable authority,” he said. “We’ve always thought of them as infallible, and so it’s startling and intriguing to see how wrongly they’ve sometimes shown the world to be.”

Brooke-Hitching first became interested in cartography as a child. His father was a rare book and map dealer who covered the walls of their home with old geographical charts.

One of his favorite hoaxes concerns Scottish explorer Gregor MacGregor, who reportedly visited London in the early 1800s with a map of a new but entirely make-believe country in South America.

Claiming to be the new nation’s king, MacGregor sold off sections of land. “Two boats full of colonists, who sold all their possessions to start a new life there, sailed to the coordinates he provided,” said Brooke-Hitching. But, unfortunately for them, they discovered “nothing but a desolate swamp.”

The phantom river of French explorer Louis Lahontan, who mapped it as running across Western US in 1703 pic.twitter.com/7EslTACijA — Ed Brooke-Hitching (@foxtosser) November 4, 2016

“What is so fascinating is that they allow you to see the world as it existed purely in the imaginations of our ancestors,” Brooke-Hitching said of the stories he investigated. “You get a sense of how exciting and terrifying the world must have been when we knew so little about it.”

Brooke-Hitching said nowadays “it feels like everything has been discovered, like the mystery has gone.” With the seemingly omniscient tech company Google and its Maps app trying to profile the entire planet, he may have a point.

“But from these maps and stories, you realize that however certain we are of the world around us, there’s usually more to the story,” the author added. “You wonder whether there are other fictitious islands or mountains drawn on our current maps that are in fact quietly enjoying a non-existence, just waiting to be undiscovered.”

Watch Brooke-Hitching talk about his new book in the clip above.