The standard theory just has too many holes in it.
‘Cart ruts’ is the term used to describe the parallel grooves cut into rock that are found scattered all over the Maltese islands. The original theory claims that these were made by vehicles transporting heavy cargo, however the hypothesis is inconclusive for several reasons.
It would be assumed that the so-called 'cart ruts', if truly made by carts passing over the same passage, should make grooves of the same depth and width all the way along the rock. However, in some places they are just a few centimetres deep and in others the depth is up to 60cm. Same goes for the width: in some places they are just 10 centimetres wide and in others up to 50 centimetres!
The width between the grooves is pretty consistent but does vary by a few inches, which is still strange enough if they were made by constant use of a vehicle, whether wheeled or on rollers as proposed in the visitor centre at the Mnajdra and Hagar Qim visitor centre. And why have no wheels or roller balls ever been found?
The shape of the groove also does not support this 'cart ruts' theory. Some ridges are in a U-shape and some in a V-shape. In addition, some are bumpy and irregular while others are finely sculpted. There are also a few instances where a single rut appears or there are several very close to each other. This is not only inconsistent but also not typical of wear and tear from a repetitive function, especially as described.
To add to the mystery, some run straight, some in curves. Some for just a few metres, some for several kilometres. Some along straight surfaces, others along rather steep hills. Many end abruptly for no apparent reason, with the left and right groove sometimes even ending at different lengths.
Their location also brings rise to some questions. Some are indeed near quarries or temples, but others are not close to anything of significance that can be identified today. Many of these cart ruts lead to nowhere in particular, certainly not always to and from the temples or quarries they are supposed to have served, and sometimes right off cliffs or into the sea.
Only about thirty of 150 cart rut sites have been linked to temples or quarries and that indicates that it is probably just a coincidence due to the also very high concentration of temples and quarries on the Maltese Islands.
Basically, there is plenty of evidence to indicate that the so-called cart ruts are not cart ruts at all. In fact, it is probably the least likely explanation for these strange parallel grooves in the ground that are found all over the world, including Portugal, the Azores Islands, Spain, France, Italy, Germany, Switzerland, Azerbeijan, Greece, Turkey, India, Brazil, Bolivia and Mexico.
With over 150 locations identified in Malta and Gozo, the Maltese Islands are the most densely concentrated area on the planet with cart ruts. And Clapham Junction (Misrah l-Ghar il-Kbir), on the outskirts of Siggiewi and Rabat, is the most concentrated area on the Maltese Islands with cart ruts, with several intersecting at junctions, hence the name given as it reminds one of the famous railway station in London.
With no conclusive evidence that these parallel grooves in the ground were indeed cart ruts, several more theories have been proposed.
Some propose that the grooves were made by some unknown technology belonging to ancient civilisations. Perhaps they were irrigation systems or they might have been filled with soil, trapping water and enabling fertile growth of crops within them. But, the question of why they would come in pairs would still remain, although that might have been down to the tool or technology used to make them.
Some propose that the grooves are related to leylines - the Earth’s energies - a theory that many attribute also to megalithic temples. With speculators considering what we call ‘temples’ as ancient architectures intended to harness sun energy, just as the pyramids would have harnessed earth energy, the grooves would have been a means to direct such energies as required.
Another speculation is that the grooves were made by ancient aliens for some purpose to do with their spacecraft. Despite sounding far-fetched and this possibility being downright dismissed by mainstream archaeologists, plenty of evidence exists suggesting a historic existence of some very advanced technology on Earth in previous eras.
Indeed, several out-of-place artifacts (OOPArt) exist. These are artefacts of historical, archaeological or paleontological interest found in an unusual contex that challenges conventional historical chronology. And the presence of cart-ruts in the sea or running from below Hagar Qim then being found on Filfla would suggest that the cart ruts existed prior to five million years ago, when the Mediterranean Sea dried up after it was sealed off from the Atlantic Ocean, or at least before the last ice age 2.6 million to 12,000 years ago, when water levels were much lower. Modern humans are not widely accepted to have lived at such time.
All the theories nonetheless suffer from some inconsistency or controversy. The mystery remains as to who made these grooves in the ground, when and why.