A marble map of ancient Rome, that hasn't been put on public view for almost 100 years, is getting its very own museum within sight of the Colosseum.

Rome Mayor Roberto Gualtieri was at the opening of the new archaeological garden and museum, and walked across the map fragments – now preserved under glass – of the famous Forma Urbis Romae.

Concealed for decades, a huge network of chambers beneath Rome’s Capitoline Hill is to be opened up to the public, revealing ...