Before the invention of the magnetic compass, navigating with a sundial would have been difficult, particularly on overcast days. Ancient Viking lore suggests that they had a magical tool to find the sun, even when the star was hidden.

Researchers have now discovered the crystal that would have made such a magical apparatus possible. The Vikings could have used a common calcite crystal, called an Icelandic spar, to find the sun in the high latitudes where they would have had to battle long twilights and cloudy skies to navigate. This special "sunstone" could find the direction of the sun even when it was out of view because it plays a trick with the light.

"The Vikings could have discovered this, simply by choosing a transparent crystal and looking through it through a small hole in a screen," study researcher Guy Ropars wrote in an email to LiveScience. "The understanding of the complete mechanism and the knowledge of the polarization of light is not necessary."

Tehran -- Eleven engravings, which are believed to date back to 40,000 years ago, have been discovered in the Teimareh region near the city of Khomein in Central Province.

The engravings depict patterns of hands, expert of ancient stone engravings Mohammad Nasseri told the Persian service of the IRNA on Sunday.

Although the engravings date back to 40,000 years ago, some Elamite pictographs, some marks of the Pahlavi and Arabic scripts, and a number of cup-shaped motifs have been etched around each engraving, he added.

According to the semiotics, the hand patterns and the cup-shaped motifs refer to a temple or a place of worship, Nasseri stated.

Once laid to rest, the remains of many who died in medieval Europe were not left in peace. As much as 40 percent of graves from the mid-fifth to mid-eighth centuries appear to have been disturbed after burial.

Grave robbers, searching for wealth buried along with the dead, have frequently born the blame from archaeologists.

"This sort of behavior has always been described as grave robbery," said Edeltraud Aspöck, a postdoctoral researcher at the Austrian Academy of Sciences. "It has always been thought that it was criminal gangs and foreigners that have been plundering, and it was all about material gain."

But after carefully examining disturbed graves, Aspöck believes something much more complex was happening.

For instance, in a sixth-century Austria cemetery, only certain types of objects appear to have been taken, and there's a pattern to how the excavated bodies were handled, indicating that more than mere plundering was occuring. And in a slightly more recent English cemetery, some corpses were discovered with their bodies placed in strange poses - possibly the work of people who reopened their graves to ease the restless souls, Aspöck suggests.

Neanderthals weren't the only ancient cousins that humans frequently mated with, according to a new study that finds that East Asian populations share genes with a mysterious archaic hominin species that lived in Siberia 40,000 years ago.

This group, the Denisovans, is known only by a few bone fragments: A finger bone, a tooth and possibly a toe bone, which is still undergoing analysis. The Denisovans likely split off from the Neanderthal branch of the hominin family tree about 300,000 years ago, but little else is known about their appearance, behavior or dress. But just as researchers have learned that ancient humans and Neanderthals mated, they've also found genetic echoes of the Denisovans in modern residents of Pacific islands, including New Guinea and the Philippines.

The new research expands the Denisovan genetic influence, uncovering Denisovan genes in modern East Asian populations. The genetic signal is less strong than it is in the Oceanic islands such as the Philippines, said study researcher Mattias Jakobsson, a professor of evolutionary biology at Uppsala University in Sweden. On the Asian mainland, the genetic similarities to Denisovans are strongest in southern China and Southeast Asia.

"We are actually finding gene flow in Southeast Asia," Jakobsson told LiveScience. "So it's not restricted to the Oceanian parts of the world."

A small box with a cross carved on its lid found in Jerusalem, containing what may have been portraits of Jesus and Mary.

Israeli archaeologists said Sunday they have found a tiny 1,400-year-old relic of Christian faith among the remains of an ancient road in Jerusalem.

The finding, an exquisitely made 2 centimeter by 1.5 centimeter box of bone with a cross carved on the lid, was likely carried by a Christian believer around the end of the 6th century A.D.

When its lid is removed, the remains of two portraits are still visible in gold and paint a man and a woman, possibly Jesus and Mary.

Archaeologist Yana Tchekhanovets of the Israel Antiquities Authority said Sunday that the box is the first well preserved example of its kind and is important because it shows that icon use was not limited to church ceremonies in Byzantine times.

A collection of Bronze Age artefacts found by a man with a metal detector in a Pembrokeshire field may end up at the National Museum Wales.

The tools, a weapon, and other items which were found by Gavin Palmer near Manorbier have been declared treasure by the county's coroner.

The museum says the find helps shed light on how people lived in west Wales 3,000 years ago.

It is having the find independently valued with a view to buying the items.

The money would be split between Mr Palmer and the landowner.

The city police on Wednesday recovered as many as 115 gold coins from the villagers of Kalugutla in Andhra Pradesh's Mahbubnagar district that were found in a farm land.

Some workers and villagers stumbled upon the gold coins that were kept in small pots while they were removing weeds from an agricultural land at Kalugutla village at Manapadu mandal on Tuesday and distributed some coins amongst themselves.

However, some villagers informed the matter to the police. So far, 115 gold coins have been recovered, a police officer said.

"After the information, we recovered 115 gold coins weighing between 1-3 grams each from the villagers. The coins appear very old. Searches are on to locate if there are some more gold coins. The Manapadu Tahasildar and Archaeological department officials are also enquiring from the villagers about the gold coins and verifying as to which era the coins date back to," he said.

Manapadu police are investigating the case further.

Some 2250 years ago in Egypt, a man known today only as M1 struggled with a long, painful, progressive illness. A dull pain throbbed in his lower back, then spread to other parts of his body, making most movements a misery. When M1 finally succumbed to the mysterious ailment between the ages of 51 and 60, his family paid for him to be mummified so that he could be reborn and relish the pleasures of the afterworld.

Now an international research team has diagnosed what ailed M1: the oldest known case of prostate cancer in ancient Egypt and the second oldest case in the world. (The earliest diagnosis of prostate cancer came from the 2700-year-old skeleton of a Scythian king in Russia.) Moreover, the new study now in press in the International Journal of Paleopathology, suggests that earlier investigators may have underestimated the prevalence of cancer in ancient populations because high-resolution computerized tomography (CT) scanners capable of finding tumors measuring just 1 to 2 millimeters in diameter only became available in 2005. "I think earlier researchers probably missed a lot without this technology," says team leader Carlos Prates, a radiologist in private practice at Imagens Médicas Integradas in Lisbon.

Prostate cancer begins in the walnut-sized prostate gland, an integral part of the male reproductive system. The gland produces a milky fluid that is part of semen and it sits underneath a man's bladder. In aggressive cases of the disease, prostate cancer cells can metastasize, or spread, entering the bloodstream and invading the bones. After performing high-resolution scans on three Egyptian mummies in the collection of the National Archaeological Museum in Lisbon, Prates and colleagues detected many small, round, dense tumors in M1's pelvis and lumbar spine, as well as in his upper arm and leg bones. These are the areas most commonly affected by metastatic prostate cancer. "We could not find any evidence to challenge this diagnosis," Prates says.

The writer Nancy Mitford spied on her sisters because of their sympathies with Hitler, documents released by the National Archives reveal.

The latest batch of files from the security service MI5 includes a report from January 1941 which says the writer "personally informed the authorities of her sister's (Lady Mosley's) treasonable sympathies.

"The information was given with very good will and is thoroughly reliable."

Lady Diana Mosley married the British blackshirt leader Sir Oswald Mosley and was a friend of Hitler.

A search of her luggage at Croydon airport on one occasion, the files state, turned up a newly signed photograph of him. She was interned in late 1940.

Evidence of a second entrance and a farmstead have been discovered beneath a complex of stone circles in Somerset.

The discovery has been made as part of an underground archaeological survey of the Stanton Drew stone circles.

The complex is the second biggest in Europe and dates back to the late Neolithic and early Bronze Age.

An earlier study in 2009 concluded the site was 1,000 years older than previously thought after an underground burial chamber was found.

'Sacred objects'

The studies, which took place in 2009 and 2010, were made by Bath and North East Somerset Council and Bath and Camerton Archaeological Society (BACAS) in a joint project.