One of the world's most famous monuments, the enormous standing rocks at Stonehenge have confused and fascinated visitors for thousands of years.  

If you've never visited the site up close, it can be hard to imagine just how impressive it is. Each of the standing stones, which once formed a full ring, are 13 feet high and almost 7 feet wide. They weigh up to 25 tonnes each, and the sheer size of the monument has raised a lot of questions.

Why was Stonehenge built?

Even after hundreds of years of intense research, experts still can't say for sure what Stonehenge was used for. It was built at least 4,000 years ago, but could date back as far as the year 3000 B.C.

We know for sure that the site was used as a burial ground, because there are hundreds of graves in and around the site. Experts say that wealthy and important families may have reserved the site as a primitive cemetery.

But there is also evidence that Stonehenge was built as part of a Pagan ritual. The points between the rocks mark places where the sun and moon rise and set, revealing it could have been an "ancient observatory."

But the real question is how were these massive blocks moved into place? A surprising source may have the answer...

While Stonehenge had been rebuilt and restored over the years using modern technology, it's hard to imagine how our ancestors got the job done.

How was Stonehenge built?

It's so hard for us to believe that people living 4,000 years ago could build Stonehenge that people have come up with some pretty daffy explanations. Magic, aliens, and other far-fetched ideas have all been used to explain the structure.

But the real answer could be very simple. A construction worker from Michigan named Wally Wallington has come up with his own method for making the monument, and he's proving it can work by building a Stonehenge in his own backyard.

Wallington uses old school techniques, including wooden ramps, "rolling fences" and pulleys, which all would have been available to Stonehenge's original builders.

His most impressive trick involves sliding tiny rocks underneath a huge slab, then turning it in circles so the huge block "walks" forward slowly. Using just gravity and his own two hands, Wally can move a Stonehenge-sized block 300 feet in an hour.

With help from some friends,  Wally is creating "Stonehenge Reloaded" in a lot behind his house, and while we don't have a finished picture of his creation, the early work seems very promising. Although, we're a little disappointed there are no aliens involved!

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