Sankt Pantaleon-Erla

It's, was the remains of a large, meticulously planned Roman city along the river that managed to go undetected for about 2,000 years.

They did these geophysical surveys near the town of St. Pantaleon-Erla in Lower Austria, showing traces of the previously unknown urban area.

It was big, too, 62 to 75 acres, systematically laid out.

You can see it's quite organized there from the picture, with gridded streets, a massive amphitheater that could accommodate about 8,000 people.

So interesting what the geophysical surveys can show us, can tell us.

The site is located within the Danube Limes, which is a UNESCO World Heritage Site spanding three... span- spanning rather 370 miles of the Roman Empire's Danube frontier, which is why it's been the site, the interest of researchers.

They've been exploring this s- about six-mile-long stretch of the Danube Limes between Austria, of the Austrian towns of Enns and St. Pantaleon-Erla.

So they think this settlement was founded about 80 CE and abandoned about a century later.