Earlier this month, a council in Scotland delivered an exciting announcement: a previously unknown and well-preserved recumbent stone circle believed to date back 4,500 years had been identified on a local farm. The find in the parish of Leochel-Cushnie in Aberdeenshire was thought to be a miniature version of the ancient monumental circles found throughout Scotland and Ireland. There was just one problem with the story—as it turns out, the find is less than three decades old.

According to the Press Association, the stone circle was actually constructed by an archaeologically minded farmer in the 1990s, something that the site’s current residents weren’t aware of when they notified authorities in November.

Historic Environment Scotland and Aberdeenshire’s archaeological service had no reason to believe the stone circle was a fake at first. As Tom Metcalfe of LiveScience reports, the site is on farmland far from any road, meaning it could have remained hidden for years, though it does not show up on any surveys of the area. A local woman now in her 80s claimed she saw the stone circle back in the 1930s.

The find was particularly thrilling because a stone circle had not been discovered in the area for 50 years, and the find was made up of multiple stones. Most stone circles in the area only consist of one or two.

In the midst of the stone circle frenzy and archaeological investigation, the former owner of the property stepped forward to say that he built the stone circle some 20 years ago, cutting research at the site short.

So how could his modern-day effort fool archaeologists? On the one hand, the investigation of the site had barely begun. Neil Ackerman, the Historic Environment Record Assistant working on the project, says in a press release that the site's completeness, smaller stones and small diameter were unusual, but didn’t cause major red flags as there can be a huge amount of variation between the stone circles. Also, there is no reliable method to date exactly when a stone was planted in the ground.

Also, as Ackerman tells Metcalfe in a separate article at LiveScience, the replica was very well done. “There are various replicas around, but they are usually not as good as this,” he says. “The guy who built this really knew what he was doing. It is quite interesting that in building a stone circle, he did not just put a bunch of stones in a circle, he has very closely copied a regional monument type.”

There is no evidence that the builder of the stone circle was intending to trick anyone. In fact, Metcalfe reports he never told anyone about constructing what had to be a difficult, labor-intensive personal project.

Tara John at CNN reports that recumbent stone circles get their name from the practice of lying one of the stones in the circle horizontally. About 99 recumbent stone circles have been found throughout Scotland to date. It’s not known what the purpose of these monuments were, but archaeologists believe they may have been used as calendars, for astrology or could have hosted ceremonial fires.