An office building from the 1930s in London was about to be demolished — until remnants of the city’s first Roman basilica were found in the basement.

The plan was to demolish the old office building at 85 Gracechurch Street in the heart of London’s financial district and construct a new 32-story tower in its place. But as demolition began, archaeologists made a staggering discovery in the site’s foundation: remarkably intact ruins of London’s first public building,

The 2,000-year-old basilica was “once the beating heart of Roman London,” the Museum of London Archaeology said.

Deep beneath a modern office building in London, archaeologists have made an extraordinary discovery – the remains of the first Roman basilica in the city. Constructed shortly after the Roman conquest of Britain,