During World War II, Lord Mountbatten and Geoffrey Pyke approached Winston Churchill with a novel plan to reach German U-boats in the mid-Atlantic, where land-based planes couldn’t reach them. They wanted to build an aircraft carrier out of solid ice.

It sounds crazy today, but if they’d gone through with it Project Habbakuk might well have lived up to its biblical billing (“be utterly amazed, for I am going to do something in your days that you would not believe, even if you were told”). Mountbatten and Pike planned to assemble 280,000 blocks of ice into a ship 600 meters long, with a displacement of 2 million tons (today’s Nimitz-class carriers are 333 meters long and displace 100,000 tons). It would carry electric motors, anti-aircraft guns, an airstrip, and a refrigeration unit to keep everything from melting.

Pro: It would be practically unsinkable.

Con: It would take 8,000 people eight months to build it, at a cost of $70 million.

In the end they made a little prototype in Alberta, but the project never got any further. Still, it’s a credit to Churchill that he even considered such an outlandish idea. “Personally I’m always ready to learn,” he once said, “although I do not always like being taught.”

A villain worthy of DC Comics, Spring Heeled Jack leapt liberally around England between 1837 and 1904, attacking isolated victims who described him as a muscular devil in an oilskin.

If he was the devil, he wasn’t a very ambitious criminal, generally just crashing carriages and groping women. But he could jump 9-foot walls, perhaps using spring-loaded footgear, judging from some ill-preserved prints.

An anonymous letter implied that a human prankster was terrorizing London on a bet, and incidental reports began to mount. In 1838 four witnesses saw him breathe fire and jump to the roof of a house, and in 1845 he threw a 13-year-old prostitute from a bridge, his first killing. On the night of Feb. 8, 1855, long trails of hooflike prints were seen in the snow throughout Devon, crossing roofs, walls, and haystacks. By 1873 thousands were gathering each night to hunt the ghost.

Nothing seemed to stop him, including bullets, and he even attacked a group of soldiers at Aldershot Barracks in 1877. He was last spotted in 1904 in Liverpool, leaping over a crowd of witnesses and disappearing behind some neighboring houses.

There’s no good explanation. Some suspected the Marquess of Waterford, who was known to spring on travelers to amuse himself, but the attacks continued after his death. Others have suggested a stranded extraterrestrial, a visitor from another dimension, or a real demon. We’ll never know.

“The most beautiful thing we can experience is the mysterious,” wrote Albert Einstein. “It is the source of all true art and science.”

That was true even in the Dark Ages, though the mysteries were a lot iffier back then. William of Newburgh records an “unheard-of” prodigy in East Anglia around 1150, when reapers were gathering produce during the harvest near some “very ancient cavities” known as the Wolfpittes. “Two children, a boy and a girl, completely green in their persons, and clad in gaments of a strange colour, and unknown materials, emerged from these excavations.”

Taken in by the villagers, they learned to eat beans and bread, which in time “changed their original color” until they “became like ourselves.” The boy died shortly after he was baptized, but his sister continued in good health and eventually married.

On being taught English, they told this story:

• “We are inhabitants of the land of St. Martin, who is regarded with peculiar veneration in the country which gave us birth.”
• “The sun does not rise upon our countrymen; our land is little cheered by its beams; we are contented with that twilight, which, among you, precedes the sunrise, or follows the sunset. Moreoever, a certain luminous country is seen, not far distant from ours, and divided from it by a very considerable river.”
• “On a certain day, when we were feeding our father’s flocks in the fields, we heard a great sound, such as we are now accustomed to hear at St. Edmund’s, when the bells are chiming; and whilst listening to the sound in admiration, we became on a sudden, as it were, entranced, and found ourselves among you in the fields where you were reaping.”

William closes: “Let every one say as he pleases, and reason on such matters according to his abilities; I feel no regret at having recorded an event so prodigious and miraculous.” It’s poetic, in any case.

Encounter with a Newfoundland mermaid, recorded by Richard Whitbourne, 1610:

“Now also I will not omit to relate something of a strange Creature that I first saw there in the yeere 1610, in a morning early as I was standing by the water side, in the Harbour of Saint Johns, which I espied verie swiftly to come swimming towards me, looking cheerefully, as it had beene a woman, by the Face, Eyes, Nose, Mouth, Chin, eares, Necke and Forehead: It seemed to be so beautifull, and in those parts so well proportioned, having round about upon the head, all blew strakes, resembling haire, downe to the Necke (but certainly it was haire) for I beheld it long, and another of my companie also, yet living, that was not then farre from me; and seeing the same comming so swiftly towards mee, I stepped backe, for it was come within the length of a long Pike.

“Which when this strange Creature saw that I went from it, it presently thereupon dived a little under water, and did swim to the place where before I landed; whereby I beheld the shoulders and backe downe to the middle, to be as square, white and smooth as the backe of a man, and from the middle to the hinder part, pointing in proportion like a broad hooked Arrow; how it was proportioned in the forepart from the necke and shoulders, I know not; but the same came shortly after unto a Boat, wherein one William Hawkridge, then my servant, was, that hath bin since a Captaine in a Ship to the East Indies, and is lately there imploied againe by Sir Thomas Smith, in the like Voyage; and the same Creature did put both his hands upon the side of the Boate, and did strive to come in to him and others then in the said Boate; whereat they were afraid; and one of them strooke it a full blow on the head; whereat it fell off from them: and afterwards it came to two other Boates in the Harbour; the men in them, for feare fled to land: This (I suppose) was a Mermaide.”