THE REAL SIGNS OF TIMES

King Tut was buried with a dagger made of an iron that literally came from space, says a new study into the composition of the iron blade from the sarcophagus of the boy king.

Using non-invasive, portable X-ray fluorescence spectrometry, a team of Italian and Egyptian researchers confirmed that the iron of the dagger placed on the right thigh of King Tut's mummified body a has meteoric origin.

The team, which include researchers from Milan Polytechnic, Pisa University and the Egyptian Museum in Cairo, detailed their results in the journal Meteoritics and Planetary Science.

Nottingham is a city with a secret: below its shops, restaurants, houses, malls and pubs lies a hidden world of caves and tunnels.

Best known to visitors for the Robin Hood legends of nearby Sherwood Forest, Nottingham is also home to more than 500 man-made caves. Dug through layers of soft sandstone, they tell a story spanning hundreds of years, from medieval monks to King Henry VIII. And a new app – detailing dozens of the caves with their histories, access information, photographs, 360-degree panorama shots and 3D fly-through videos – aims to open this underground world to visitors.

The first reference to the labyrinth beneath Nottingham dates back to the 9th Century, when the area was named Tigguo Cobauc – Welsh Anglo-Saxon for “the place of caves”. The name was given to the town by a travelling monk, who encountered a local population living inside the caves.

Some 1200 years later, this name could still apply, with some of the tunnels lying beneath surprisingly modern establishments. The City of Caves, Nottingham’s largest network of caves open to the public, lies beneath Broadmarsh Shopping Centre.

A labyrinth of tanneries, air raid tunnels and slum housing, the oldest sections of the City of Caves date back to the 4th Century. Early inhabitants dug into the soft sandstone to create a cosy place to sleep – temperatures in the caves stay a constant 16C year-round.

By the 15th Century, people were no longer living underground, but the caves had taken on a second life as cesspits – used for fertilising the city’s farms and the supplying the tanneries with waste for the leather making process.

The City of Caves’ tannery – the country’s only underground tannery – might have also saved Nottingham from one of the history’s darkest periods. The town was one of the few places in Britain to remain free of the plague and it is believed the tannery caves prevented rodents from nesting and breeding within the area.

The caves’ lifesaving abilities didn’t end with the plague. As a manufacturer of ammunitions, Nottingham was severely bombed during World War II. Ideal for absorbing the impact of bombs, 86 of the caves were converted into air raid shelters. The sandstone caverns saved thousands of lives.

Other caves and passageways were used for far more nefarious purposes. The infamous Mortimer’s Hole, for example, lies under Nottingham Castle, which was built in 1067 and has taken on many forms over the years. The eerie 300-step passageway winds down from the castle through rock to England’s oldest inn, Ye Olde Trip to Jerusalem, which dates to 1189.

The tunnel takes its name from Sir Roger Mortimer, who, together with Queen Isabella, is rumoured to have killed Isabella’s husband King Edward II and taken the throne for themselves.

On the night of 19 October 1330, the young King Edward III and a band of his loyal supporters entered the tunnel. They burst into his mother Isabella’s bedroom, seizing the pair. Sir Roger was hanged at the Tower of London; Isabella, escaping with a much lighter sentence, was forced into retirement.

But far more everyday establishments than Nottingham Castle have underground caverns. “If you manage a pub in the city, I'd say nine out of 10 times you would have caves. They're everywhere,” said Tom Flynn, manager of the Bell Inn, one of Nottingham’s oldest pubs.

Tree-ring dating suggests that local Carmelite monks built the first public house on the site in 1420. The Bell Inn’s cave system, which is large enough to extend under the adjacent buildings, includes two wells that the monks used for drawing water to brew their ales.

The Bell Inn remained in the monks’ hands until King Henry VIII’s dissolution of the monasteries in 1539; at that point, it became a secular alehouse. During World War II, a section of brickwork in the cave was put up by the Ministry of Defence, who hoped to use it as a bomb shelter – a plan they changed after discovering a river ran along the back wall. Today, the Bell’s caves are very much a working cellar, stocked with beer and wine and with cask ale pipes going up to the bar.

While the Bell’s caves feel bright and lived in, there are much spookier caves under the Ye Old Salutation Inn, which dates back to 1425. The Salutation’s cave system consists of rock cut passageways, cells, chambers and chimneys, all dug out at various points in the Medieval, Georgian and Victorian times.

There is even a ghost: a young girl called Rosie. In one of the darkest corners, visitors leave drinks, marbles and dolls for her. “I'm a sceptic where ghosts are concerned, but I've seen things in this pub that really do make me wonder,” manager Terry Webster said.

At 6:20 one morning, Webster said he was going downstairs to the pub when he heard footsteps and a cough. Thinking staff from the night before had forgotten to lock up, he ran down to the bar to nab the intruder, but there was no one to be found. A review of the pub’s security footage also came up empty.

Pulling all of this extensive, underground history together – ghosts aside – is the Nottingham Caves App, the result of on-going work by Trent & Peak Archaeology. Project manager Dr Paul Johnson said that of the 500-odd known caves in Nottingham, 76 have been investigated and recorded in detail. The team weren't able to record as many of the caves as they had initially hoped as many were more complex than they first thought.

"You're not just doing a structural record. You're also recording things like graffiti on the walls, individual elements of sculpture and things like that,” Johnson said. “So the time involved in doing it multiplies quite quickly."

Even so, during the survey, the team found evidence of gentlemen’s clubs, bowling alleys, summer gardens and industrial spaces.

Johnson said plans are underway to continue mapping and recording the caves with the help of local volunteers. After undergoing confined spaces and basic recording training, the volunteers will go out and speak to property owners, identify new caves and – where it's safe – go in and complete a quick survey. They hope to begin work in the first half of 2016.

Ultimately, the idea is to open up more of Nottingham’s underground to visitors – allowing more people to appreciate the unique history found beneath the city.

This story is a part of BBC Britain – a series focused on exploring this extraordinary island, one story at a time. Follow us on Facebook, Twitter and Instagram.

“How do you like spiders?” asked James Gossip, an archaeologist, British prehistory expert and my guide to this subterranean world – one, apparently, that’s already inhabited. I looked at him, blanching slightly. He laughed. “Shall I just not point them out?”

“Maybe not,” I said, peering into the dark tunnel before us.

I’d come to nearly the very tip of Cornwall, the southwestern peninsula of England, in search of an ancient mystery: the underground passages built here some 2,400 years ago.

As a casual observer, you’d never know this part of the country had prehistoric surprises in store.Halliggye Fogou, on Cornwall’s Lizard Peninsula, is not only off the tourist track – it’s off any beaten track. The largest town within a 10-mile radius, Helston, has just 12,000 residents. The lush green hills are dotted with cows and itty-bitty villages lacking even a post box.

From this picture-perfect Cornish countryside, only a trained eye can pick out the complex tapestry of mounds, bumps and stones left by 150 generations working the land. “Do you see that, over where the windmills are?” Gossip asked me later, pointing to the nearly imperceptible humps on a hill in the distance. “That’s covered by Bronze Age barrows.” Enclosures – those bumpers of land that once surrounded a farm or settlement – are everywhere. And the landscape is littered with the remnants of roundhouses, stone circles and ramparts.

Gossip, though, is most interested in what people were building underground. Fourteen tunnels – called "fogous” after the Cornish word for cave “ogo” – have been found in Cornwall. Similar to the souterrains found in Scotland, Ireland, Brittany and Normandy, fogous haven’t been discovered anywhere else in England. Unlike, say, the labyrinthine copper mines tunnelled out 3,800 years ago in Wales, fogous (and souterrains) weren’t merely dug. They were built. To make them, it’s thought that people opened up deep trenches in the ground, sided them with stone slabs, topped them with capstones and filled in the area above them.

For an Iron Age society, this required a serious devotion of time and resources – and no one knows why they would have done so.

Some of the difficulty is that many of Cornwall’s fogous may already have been emptied. This may have been done by the people who actually used them. Or it may have occurred far later. “Many of them were excavated by antiquarians, so we don’t have many good records for what was found,” said archaeologist Susan Greaney, head properties historian at English Heritage, who specialises in prehistory. “There are only a couple that have been excavated in modern times – and they don’t seem to be structures that really easily give up their secrets.”

Take Halliggye Fogou, the best preserved fogou in Cornwall. Its first, 1.8m-high chamber is large enough to easily move around in. But at the end of the 8.4m passage, it abruptly narrows into another, 4m-long tunnel, one just 0.75m tall. “It’s something anyone would have to crawl along,” Gossip pointed out.

Another tunnel branches to the left off the entrance tunnel. At 27m, it’s three times the length of the first chamber – the distance of two double-decker buses laid end to end – and became progressively darker as we walked further inside. Darkest of all, though, was the final creep, tucked to the left of the end of the passage. Complete with a stone lip jutting up to trip you, the entrance was so narrow and awkward I had to put down my clunky camera in order to clamber through.

In other words, none of it seemed designed for easy access – a characteristic that’s as emblematic of fogous as it is perplexing.

“A lot of the discussion around fogous is what they were for, because they’re really strange,” Gossip said. “Many people talk about them as a place to hide.”

But as he switched off his torch, the likelihood of the hypothesis vanished along with the light. Damp, chilly, and the kind of black that modern-day humans don't tend to witness, it seemed a strange sort of hideaway for even the most desperate of times – or even with the most reliable of flames. “A person wouldn’t have wanted to spend much time in here,” he said.

Meanwhile, although these tunnels seem “secret” to us today, they weren’t necessarily then. Many have lintels that would have been visible from the surface, for example – making them an odd hiding place from intruders.

Over the years, other hypotheses have surfaced. Perhaps fogous were burial grounds: when Reverend Richard Polwhele recorded entering the Halliggye Fogou in 1803, he wrote that it “contained urns”. But the access hole that he made in its roof was used by other enthusiasts in ensuing years, and any urns are now gone. No evidence of burial, whether cremation ashes or bone, has been found in any of the six fogous that have been examined with modern archaeological techniques.

Were they used for storage? The soil is acidic, which helps explain the lack of organic material, like grain and bone. Still, it’s an impractical design for a cold store. As Greaney put it: “If you’re going to build an underground fridge, you’re going to want to be able to step in and out of it.”

And if fogous were used for valuables or metals – like local tin, perhaps – the quirky, yet likely still visible, design is odd; so is the fact that not a single ingot has been found.

The last prominent theory also seems unsatisfying, if only because it’s a frequent go-to for archaeologists who study a period as little understood as this one: maybe they were mainly ceremonial. Perhaps they were meant to be accessed only by the elite, with the restricted space echoing the restrictions of social class. Or perhaps they were places to commune with the gods.

“These were lost religions. We don’t know what people were worshiping,” Gossip said. But, he added, since they were often used over hundreds of years, their purpose probably shifted. And perhaps the real answer was all of the above: “There’s no reason they couldn’t have had a ceremonial, spiritual purpose as well as, say, storage.”

Richard Strachan, senior archaeologist for Historic Environment Scotland, manages the nine souterrains under the public body’s care. Archaeologists have faced many of the same conundrums there, from the odd shape of the tunnels (in Scotland, Strachan said, they’re banana-shaped, curving around a roundhouse, or in a cruciform) to the cleaned-out nature of their interiors. He agrees they probably had more than one use.

“I think they’re multi-purpose,” Strachan said. “Maybe seasonal, as well. Maybe you use them for storage, then when you don’t need them for storage, you use them for ceremony.”

Gossip is hoping that another site, located just three miles northeast of Halliggye Fogou, might reveal a bit more. Like many of the others, the Boden Fogou was found serendipitously – a farmer struck a pit while laying pipe in his field in 1991. Five years later, it happened again, his tractor opening up a hole in the ground. Both holes led to tunnels.

Ensuing excavations, which Gossip has run with volunteers each summer since 2003, have turned up not only an S-shaped fogou, but roundhouses and enclosures. In fact, every recorded fogou has been found within settlements.

One 3,400-year-old roundhouse that the team excavated was abandoned 300 years after its construction. It contained more than 3,000 artefacts, mainly shards of ceramics. In a pattern seen at other roundhouses in Britain, they weren’t where they would have fallen naturally – the shards seem scattered deliberately across the floor. Some came from an enormous, elaborately decorated vessel at least 0.92m high. “It’s the largest Bronze Age vessel found in Cornwall, if not in Britain,” Gossip said.

The S-shaped fogou was dug 700 years after the roundhouse was abandoned, carefully skirting the roundhouse site. “When people come here in 400BC, they don’t disturb the place, perhaps out of respect,” Gossip said. About 500 years later, it too was deliberately closed, perhaps in a similarly ceremonial way. Early Iron Age pottery was placed on the bedrock floor, the roof was removed and dirt and stone from the surrounding bank shovelled in.

This is a pattern also seen with other souterrains. All of it seems to speak to a kind of closing ceremony. But for a structure built to do… what?

What, I asked Gossip, could he find in his excavations that might help answer the question? Is there a Rosetta Stone for fogous?

“I would like to find something that suggested a more ceremonial purpose,” he said. He paused. “But no matter what you found, there would still be discussion.”

This story is a part of BBC Britain – a series focused on exploring this extraordinary island, onestory at a time. Readers outside of the UK can see every BBC Britain story by heading to theBritain homepage; you also can see our latest stories by following us on Facebook and Twitter.