A solitary lantern hangs between the rows of large columns in Saint Peter's Square, Vatican City. The centuries old colonnades are made of travertine stone, a common material of buildings in Rome, and throughout Italy. Travertine is a limestone formed from mineral or hot springs. The word itself derives from an Italian word meaning
"of Tibur", an ancient Roman town, which is today called Tivoli, near Rome.
It was a preferred stone of Michelangelo... and Bernini, the builder of the
colonnades pictured here.
