One of Bulgaria's grandest archaeological finds in recent years is also its most puzzling.
Located in the Thracian Plain just outside Plovdiv, Bulgaria's second largest city, it is hidden in a huge mound where the digs are still ongoing. Despite the media frenzy and speculations that the enormous structure emerging from the ground is anything from the tomb of a Roman emperor to the deed of extraterrestrials, no one actually knows what this really is.
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