Archaeologists exploring the site of a planned 32-story office tower announced Thursday that they have unearthed the remains of a Roman basilica that once stood at the heart of the city known as Londinium.

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.

Archeologists exploring the site of a planned 32-story office tower announced Thursday that they have unearthed remains of a Roman basilica that once stood at the heart of the city known as Londinium.

Experts are surprised at how much of the basilica, or town hall, survived. The ancient building was part of Roman London’s political and commercial center.

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

While exploring the site of a 32-story planned skyscraper in London, archaeologists unearthed the ruins of a nearly 2,000-year-old Roman basilica.

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,