Now - after a decade of careful harvesting - experts are hoping to find out more about the life of a hill farmer in the Iron Age.
The structure was built high above the Powys countryside near Welshpool but has always been obscured by trees.
Now - after a decade of careful harvesting - experts are hoping to find out more about the life of a hill farmer in the Iron Age.
Towering 1000-feet above the Montgomeryshire countryside Breidden Hill was an obvious choice for a safe easily-protected settlement.
Now for the first time archaeologists can at last see the contours of a huge iron age hill fort first built and occupied more than 2000 years ago.
For the past decade trees covering the site have been carefully harvested to ensure one of Wales's most significant hillforts wasn¿t damaged.
It may look like just a pile of old stones now but 800 years before Christ the same rocks were formed into 20 feet high walls providing a safe haven for local farmers.
Ancient community
"Inside there would have been timber buildings, perhaps 15 to 20 feet in diameter with conical thatched roofs," said archaeologist Chris Musson.
"There were probably a fairly substantial number of occupants."
For more than 1,000 years the steep stone ramparts protected an ancient hilltop community.
Now it is hoped clearing the trees here will tell archaeologists more about just how those people lived.