On Nov. 30, 1896, two young boys came across an unidentified carcass on the beach near St. Augustine, Fla. Pale pink and rubbery, it was huge, 18 feet long and weighing an estimated 5 tons.

An analysis in 1971 agreed with early guesses that it was a gigantic octopus — in this case almost unthinkably huge, “with arms 75 to 100 feet in length and about 18 inches in diameter at the base — a total spread of some 200 feet.”

More recent studies in 1995 and 2004 say it was “the skin of an enormous warm-blooded vertebrate,” probably the entire blubber layer of a whale. Ick.

In 1832, a human skeleton was unearthed in a sandbank in Fall River, Mass. A triangular plate of brass covered its sternum, and it wore a broad belt of brass tubes. The grave also contained a number of brass and copper arrowheads. To judge from the skull, the skeleton had belonged to a young man, but from where? The local Indian tribes did not work brass.

One commentator claimed it as evidence that the Phoenicians, Carthaginians, or Egyptians had discovered North America in the remote past. Later historians speculated that an early Norse explorer might have traveled south from Newfoundland, but the style of armor was unknown to medieval Norway. A third possibility is that it belonged to an early European colonist, perhaps a Portuguese explorer.

The skeleton was destroyed in a fire in 1843, so there’s no way now to date the remains scientifically, or to gather any further information. Its identity must remain a mystery.

The following remarkable account of the stoppage of Niagara Falls, appeared in the Niagara Mail at the time of the occurrence: “That mysterious personage, the oldest inhabitant, has no recollection of so singular an occurrence as took place at the Falls on the 30th of March, 1847. The ‘six hundred and twenty thousand tons of water each minute’ nearly ceased to flow, and dwindled away into the appearance of a mere milldam. The rapids above the falls disappeared, leaving scarcely enough on the American side to turn a grindstone. Ladies and gentlemen rode in carriages one-third of the way across the river towards the Canada shore, over solid rock as smooth as a kitchen floor. The Iris says: ‘Table Rock, with some two hundred yards more, was left dry; islands and places where the foot of man never dared to tread have been visited, flags placed upon come, and mementoes brought away. This unexpected event is attempted to be accounted for by an accumulation of ice at the lower extremity of Fort Erie, which formed a sort of dam between Fort Erie and Buffalo.'”

— Barkham Burroughs’ Encyclopaedia of Astounding Facts and Useful Information, 1889

The magnificently named Lake Winnipesaukee Mystery Stone is just that — an odd carven stone, about 4 inches long, turned up by workmen digging a fence post in New Hampshire in 1872.

No one knows who carved it, when, or why. On one side are carved an ear of corn, a deer’s leg, and several other figures. One the other side are inverted arrows, a moon shape, a spiral, and some dots.

When the stone first came to light, the American Naturalist suggested that it “commemorates a treaty between two tribes.” But after an analysis in 1994, state archaeologist Richard Boisvert said that the holes drilled in the top and bottom are more consistent with power tools from the 19th or 20th century. He said that scratches in the lower hole suggest that the stone was placed on a metal shaft and removed several times. We’ll never know its real origin.

Like Namibia’s Skeleton Coast, the Shipwreck Coast of Australia combines rare beauty with treacherous seas. Explorer Matthew Flinders said, “I have seldom seen a more fearful section of coastline.” More than 50 ships have been lost here, most of them supply ships carrying immigrants and convicts to Victoria and New South Wales in the 1800s, but the coast’s strangest victim may have come much earlier.

Periodically since 1836, travelers have reported stumbling on the wreck of a very old ship of “hard dark timber — like mahogany.” The descriptions are quite specific. Here’s a letter by Captain John Mason of Belfast, published in the Melbourne Argus on April 1, 1876:

Riding along the beach from Port Fairy to Warrnambool in the summer of 1846, my attention was attracted to the hull of a vessel embedded high and dry in the Hummocks, far above the reach of any tide. It appeared to have been that of a vessel about 100 tons burden, and from its bleached and weather-beaten appearance, must have remained there many years. The spars and deck were gone, and the hull was full of drift sand. The timber of which she was built had the appearance of cedar or mahogany. The fact of the vessel being in that position was well known to the whalers in 1846, when the first whaling station was formed in that neighbourhood, and the oldest natives, when questioned, stated their knowledge of it extended from their earliest recollection.

Despite well-financed searches in 1890, 1992, 1999, and 2004, no trace of the ship has been found. If it ever existed, it may have been the missing ship of Portuguese sea captain Cristóvão de Mendonça, which was wrecked in 1522. If that’s true, there’s a strange irony here: The introduction of livestock and pests from Europe have destabilized the local dunes, which may have buried all evidence of Australia’s first European visitor.

Accomplishments of Lewis Gordon Pugh:

• One month after his first swimming lesson, swam from Robben Island to Cape Town, South Africa
• Shortly thereafter, swam the English Channel
• First person to swim around the southernmost point in Africa, the northernmost point in Europe, the Cape of Good Hope, and the Cape Peninsula
• First person to complete a long-distance swim in all five oceans
• First person to swim down the entire length of Norway’s Sognefjord, 204 kilometers
• First person to swim across an African Great Lake (Lake Malawi)
• Gold medal in the 500-meter freestyle at the 2006 World Winter Swimming Championships in Finland
• World record for the northernmost long-distance swim (Spitsbergen, 1,000 kilometers from the North Pole) and southernmost long-distance swim (Petermann Island, off the Antarctic Peninsula)

Most recently Lewis became the first person to swim the entire length of the River Thames, to raise awareness about the problems of global warming. Along the way, he stopped in London to visit Tony Blair.