Archaeologists have finished excavating a once-glorious arts center in the heart of Rome that was only discovered because of an underground railway line, the Guardian reports. "Hadrian's auditorium is the biggest find in Rome since the Forum was uncovered in the 1920s," said Rossella Rea, the project's chief archaeologist. But its three huge halls, 36-foot-high arched ceilings, and fine marble flooring lay unknown to Romans until railway engineers recently ran into it—and had to abandon plans for two stations in the center of the city.
Emperor Hadrian built the 900-seat arts center in AD 123 so people could hear poetry readings and philosophical tracts. But it fell into disrepair after the fall of the Roman empire, was damaged during an earthquake in 848, and used as the cellar of a hospital in the 16th century. Now it's a hole in one of Rome's busiest roundabouts—where engineers still hope to save plans for one train station. "I believe we can run one of the exits from the station along the original corridor of the complex where Romans entered the halls," said Rea.