Believed to be constructed sometime around 300 BC, this megalithic pyramid was found buried under a hill, and no one knows why.

Some believe this gigantic structure, twice the size of the great pyramid of Giza, was buried when the Aztecs realized the Europeans were invading. Others believe that because it was constructed with mud bricks, plant life was able to grow on it.

Likely the latter, the temple was forced to be abandoned around the 7th or 8th century AD.

Known as the Great Pyramid of Cholula (locally known as Tlachihualtepetl (man-made mountain)), this beast stands around 216 feet tall and 1,475 feet wide, dwarfing all other ancient man-made structures.

Though still buried in the hill, it has become home to multitudes of tourists each year.

Image Credit

The world's largest pyramid is still buried under a hill in Mexico