There are many things humankind still doesn't understand about the Stonehenge, but one puzzle piece has been unearthed: the role of Pythagoras' theorem in its assembly.

More impressively, these ancient pillars were built 2,000 years before this great Greek philosopher even walked the Earth. It turns out, ancient folks have long been clued in to the sophisticated theorem even before it has not yet been recorded.

Pythagorean Triangles In The Stonehenge

A new book titled Megalith: Studies in Stone delves deeper into the creation of Stonehenge, suggesting that the ancient structure was constructed by applying Pythagoras' famous theorem.

Pythagoras' theorem simply states that the squares of the two legs of a right triangle always add up equal to the square of the hypotenuse, which is the side opposite of the right angle.

The Telegraph reports that in the ancient pillars' earliest incarnations in 2750 B.C., the rectangle of the four Sarsen stones can be divided in two diagonally to create a 5:12:13 Pythagorean triangle. Furthermore, the resulting eight lines that extend from the rectangle and the triangles align to specific dates of the Neolithic calendar, including the solstices and the equinoxes.

Advanced Science In Ancient Times

Ancient humans may be thousands of years behind modern technology, but they were very capable and form the earliest versions of a lot of the advanced scientific concepts.

"People often think of our ancestors as rough cavemen but they were also sophisticated astronomers," John Matineau, the editor and one of the contributors to the new book, explains in the Telegraph. "They were applying Pythagorean geometry over 2,000 years before Pythagoras was born."

He adds that geometric shapes such as triangles that have been spotted in ancient structures are considered simple and early versions of Pythagorean geometry. Ancient ancestors are also well-versed solar and lunar movements.

Woodhenge, just two miles away from Stonehenge, also makes use of Pythagorean triangles along with other ancient sites.

Stonehenge reportedly used to have 56 stones or wooden posts around it, which tracked the sun and moon, predicting lunar phases as well as eclipses.

Another contributor to Megalith is megalithic expert Robin Heath, who says that ancient people often used ropes and pegs in megalithic structures to measure time periods — giving birth to the common phrase "a length of time."

He stresses that Neolithic builders are very capable and learned.

"These days it's seen as hippy dippy or New Age, but actually it's a colossal omission to the history of science that we don't see these monuments for what they are," Heath says.

Thousands trooped to the Stonehenge for 2018's summer solstice on Thursday, June 21, to watch the sun rise in direct alignment with the monument's Heel Stone and Slaughter Stone. This phenomenon only happens on the day of the summer solstice, the longest day of the year, according to Inverse.