The massive structure had been hiding in plain sight for centuries.

ARCHAEOLOGY
The researchers date the rock chip between 44,000 and 49,000 years old.
The ravages of "phossy jaw"—necrosis of the jaw bone caused by phosphorus poisoning—may have been discovered in a young teenager's remains.
The stone lines depict what's believed to be a mythological animal sticking its tongue out.
The ship was likely scuttled before the 1778 Battle of Rhode Island.
Archaeologists had to re-think much of what they knew about Monroe's life when they uncovered a large stone house on his estate's grounds.
A chemical analysis of ancient pottery shards sheds new light on the origins of mountain dairying.
This discovery might provide new knowledge into the early years of the ruler’s 22-year reign.
Literacy was already on the rise in the ancient Kingdom of Judah by the time of the Babylonian conquest in 587 BCE.
Neolithic humans may have transported the red deer from central Europe, which would make them far better seafarers than previously believed.
The contents of an ancient tomb in Upper Mustang include beads and textiles only made in India and China.
Researchers claim they can confirm the location, thanks to the biological evidence the horses left behind.