The answer to one of the great questions of all time -- "How did the Egyptians build the pyramids?" -- has apparently been in sight for hundreds of years, but previously dismissed by scientists as a form of ritual.

Recently, however, physicists from the University of Amsterdam took another look at a wall painting included in the tomb of Egyptian ruler Djehutihotep, discovered in 1817, and realized the artwork, depicting a person standing on the front of a pulled sledge and pouring water over the sand just in front of it, offered a direct explanation of how builders during that time moved heavy objects.

Findings of the new research have been published in the journal Physical Review Letters.

For the construction of the pyramids and other huge monuments, ancient Egyptians clearly had to transport giant statues and blocks of stone across the desert. To accomplish such feats, they stacked the gargantuan objects on sledges that workers pulled across the sand.

It turns out those monument runs were likely made substantially easier by the water that was poured in front of the sledges, thanks to the physical properties of sand when it gets wet.

Experiments revealed that the force needed to pull something over the Egyptian desert decreased proportionally in relation to the stiffness of the sand.

With the correct quantity of water, said the researchers, wet desert sand is about twice as stiff as dry sand -- and a sledge glides about 50 percent more easily over firm sand, just because the grains don't pile up in front of it as it pushes forward.

By placing a laboratory version of the Egyptian sledge in a tray of sand, the physicists were able to figure out how the addition of water affected the sand stiffness and required pulling force.

The stiffness of the sand was measured with a rheometer, a mechanical device used to measure the way a liquid, suspension or slurry flows when forces are applied to it.

Besides revealing how the Egyptians may have conquered one of the most daunting of engineering projects, the results, say researchers, also provide a greater understanding for many modern-day applications, since the physical properties of granular material like sand, concrete or coal continue to somewhat be scientific mysteries.