Last July 2007 an excavation for Sant'Anna, a new hospital near Como Italy uncovered a "double concentric circle of ancient stones".  It may date back to 3000 BCE and "the site is a "highly articulated prehistoric structure that could be either an ancient astronomical observatory or a sacred space," according to Stefania Iorio, Archaeological Superintendent of the region."  The diameter of the circles is around 229 feet and they are divided by a pathway of paved stones. 

The site is a rare site with no similar examples in Northern Italy.  Giancarlo Frigerio, chairman of the Società Archeologica Comense theorizes that it may be an ancient tumulus.  What makes this tumulus so unusual is size since it covers an area of approximately 13,000 feet, over 2 miles, while other tumuluses found in the same region average a diameter of 13-16 feet. Tumulus is latin for mound or small hill that was typically a man-made, mound formation erected over a grave site.

There are now plans to protect the area and create a park where visitors can access the site.

News Source: Archaeo News