Italian archaeologists have found an intriguing Stonehenge-like "calendar rock" in Sicily.

Featuring a 3.2-foot diameter hole, the rock formation marked the beginning of winter some 5,000 years ago.

The holed Neolithic rock was discovered Nov. 30, 2016 on a hill near a prehistoric necropolis six miles from Gela, on the southern coast of Sicily, by a team who was surveying some World War II-era bunkers.

"It appeared clear to me that we were dealing with a deliberate, man-made hole," archaeologist Giuseppe La Spina told Seeker. "However, we needed the necessary empirical evidence to prove the stone was used as a prehistoric calendar to measure the seasons."

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Using a compass, cameras and a video camera mounted to a GPS-equipped drone, La Spina and colleagues carried out a test in December at the winter solstice. The idea was to find out if the rising sun at solstice aligned with the distinct hole in the rock feature. According to La Spina, the experiment was "a total success."

"At 7:32 am the sun shone brightly through the hole with an incredible precision," La Spina said. "It was amazing."

The 23-foot high holed stone would have marked a turning point of the year and the seasons, anticipating some hard and cold time ahead. The moment likely had a ritual importance. In fact, further investigation of the area revealed the site was a sacred place at the end of the third millennium BC.