(CNN) — Some shoot out of the soft rock like reptiles bathing in the sun. Others are mysterious depressions resembling an ancient board game played all over the world. And a few are straight-up puzzling.
On a desolate and windswept corner of Qatar's northeastern coast, among the sand dunes of the barren desert, lies Al Jassasiya, the Gulf country's largest and most important rock art site.
Here, people centuries ago used a series of low-lying limestone outcrops as a canvas on which they carved symbols, motifs and objects that they observed in their environment.
Overall, archaeologists have found a total of some 900 rock carvings, or "petroglyphs," at Al Jassasiya. They are mostly enigmatic cup marks arranged in various patterns, including rows and rosettes, but also eye-catching representations of sailing ships, usually seen from above but also depicted in linear profile, among other symbols and signs.
"Although rock art is common in the Arabian Peninsula, some of the carvings in Al Jassasiya are unique and cannot be found anywhere else," Ferhan Sakal, head of excavation and site management at Qatar Museums, told CNN, referring to the petroglyphs of ships seen from a bird's-eye view.
"These carvings represent a high degree of creativity and observation skills [on the part of] the artists who made them," he said. "Also [of] abstract thinking, as they were not able to see the dhow (a traditional ship) from above."
Cup marks
Experts say the rock carvings at Al Jassasiya are unique to the location.
Courtesy Dimitris Sideridis
There are about 12 notable petroglyph sites in Qatar, located mostly along the country's coasts -- though some carvings can even be seen in the heart of Doha's Al Bidda Par, overlooking the Corniche, a popular waterfront promenade.
Al Jassasiya, about an hour north of Qatar's uber-modern capital and near the old pearling port of Al Huwaila, was discovered in 1957. Over six weeks in late 1973 and early 1974, a Danish team led by archaeologist Holger Kapel and his son Hans Kapel undertook a study which painstakingly cataloged the entire site in photographs and drawings.
Of all the documented single figures and compositions, more than a third consist of cup marks in various configurations, shapes and sizes.
The most prominent pattern involves two parallel rows of seven holes, leading some to believe that these were used to play mancala, a board game popular in many parts of the world since antiquity in which two contestants drop odd and even numbers of small stones into the depressions.
Others have disputed this theory, pointing to the fact that some of the holes at Al Jassasiya are too small to hold any of the stones, while others can be found on slopes -- an impractical choice that would have resulted in the counters falling out.
Further suggestions include the cup formations being used in some way for divination; or for the sorting and storage of pearls; or as systems to compute the time and tides.
Game theory
The area contains about 900 carvings.
Courtesy Dimitris Sideridis
So, what were they actually for and what do they mean?
"It is very difficult to answer," acknowledged Sakal, who also does not side with the board-game theory. "We have no direct clues about the motifs used in Al Jassasiya," he said.
"In my opinion, they might have a ritual meaning and function, which is very old so that it cannot be explained ethnographically."
But how old? "We really do not know," conceded Sakal, explaining that petroglyphs -- and rock art, in general -- are very challenging to date.
"There are wild hypotheses about the age, ranging from Neolithic to late Islamic times," he added. "I personally think that not all carvings were made at the same time."
A decade ago, one scientific study of nine different petroglyphs at Al Jassasiya found no evidence of them being more than a few hundred years old, but the researchers concluded that more studies are needed, including the development of new techniques specific to limestone carvings.
While experts cannot surely say when the Al Jassasiya petroglyphs were created, and by whom, they all agree that the most fascinating -- and unusual -- carvings at the site are those of the boats.
Theories vary on the age of the petroglyphs.
Courtesy Dimitris Sideridis
These creations provide important information about the types of vessels used in the thriving fishing and pearling industries (for centuries, the mainstays of Qatar's economy), as well as their various elements.
Most of the boats seen from above are usually fish-shaped with pointed sterns and rows of oars, carved with a pointed metal tool.
They contain several details, such as crossing ribs and holes likely showing the placing of masts and thwarts.
In some cases, a long line from the stern depicts a rope ending either in a traditional Arabic anchor (triangular stone anchor with two holes) or a European one (a metal anchor with a long shank and two curved arms, first used in the region about seven centuries ago).
Journey to the afterlife
Mystery prevails over the purpose of some of the carvings.
Courtesy Dimitris Sideridis
"On some of the boats the oars are not parallel, as they would have to be when used for rowing, but pointing in different locations," Frances Gillespie and Faisal Abdulla Al-Naimi wrote in "Hidden in the Sands: Uncovering Qatar's Past."
"This is how they would have looked when the boats were anchored out on the pearl banks and the oars were left in place for the divers to cling to and rest each time they came up."
Experts say they can only speculate as to why there is such a high concentration of ship carvings at Al Jassasiya, compared to other coastal petroglyphic sites in Qatar.
"Ships held a powerful role in the beliefs of ancient peoples, who saw them as a symbolic means of transit from this world to the next," Gillespie and Al-Naimi noted.
"Both Babylonians and ancient Egyptians believed that the dead reached the afterworld upon a ship. Greek myths spoke of the ferryman Charon who carried the souls of the dead across the river Styx to the underworld. It may be that the oldest of the ship carvings are echoes of a folk memory reaching far back into pre-historic times."
Whatever the reason, visitors should remember to take water with them and wear a hat and sunscreen when wandering among the carvings to ponder their meaning.
The fenced site does not have any shaded areas, so the best times to visit are at sunrise and sunset. Al Jassasiya is located just south of the popular Azerbaijani Beach, so an excursion there can also be combined with a relaxing day beside the sea.