The mosaic fills the wall of a room in an ancient home near the Colosseum that once belonged to a Roman Senator and dates to the 2nd Century B.C., when Rome was still a Republic. The first Roman emperor, Augustus, ruled in the 1st Century B.C.

The mosaic is in what would have been a banquet room, officials said, made to look like a cave. Making up the mosaic is a combination of glass, shells, blue tiles, and white marble. One part of the mosaic depicts a coastal city and large ships in the nearby sea; on the wall are lead pipes that would have fueled a water feature, which would have been a topic of conversation if not a sign of riches. Officials said that the house had multiple stories and also sported a large garden. The townhouse containing the mosaic is between the Forum and the Palatine Hill, not far from the Colosseum. The site is within the Colosseum Archaeological Park.

The Italian Culture Ministry said that archaeologists had uncovered the initial signs of the mosaic in 2018 and had worked painstakingly since then–with a break because of the COVID-19 pandemic– to uncover the artworks more fully. The plan is for the site to be open to the public in 2024.