How and Why Roman Ruins Are Underground: The “Lasagna City” of Rome

One of the fascinating aspects of Rome is the layering of history beneath its streets, earning it the nickname “lasagna city” among tour guides. This analogy to lasagna comes from the stacked, complex layers of historical remains that span from the ancient to the modern, creating a rich tapestry of buried ruins. But how did these layers form over time?

1. Natural Sedimentation and Urban Rebuilding

Over centuries, the Tiber River would flood periodically, depositing layers of silt and debris across the city. Each flood would create a new layer of sediment over roads, buildings, and other structures. Additionally, as buildings aged or were destroyed (from fires, invasions, or natural decay), new structures were often built right on top of the old foundations, creating a cumulative effect. By the Middle Ages and Renaissance, parts of ancient Rome were several meters below the surface.

2. Reuse of Materials

After the fall of the Roman Empire, many of its iconic structures fell into disuse or were partially dismantled. Stones, columns, and marble decorations from ancient buildings were repurposed for new constructions. This contributed to the disappearance of visible ruins and left only foundations and remnants buried below ground.

3. Changing Urban Landscape

Through Rome’s long history, its landscape changed drastically. Areas like the Roman Forum and parts of the Colosseum’s surroundings were abandoned and eventually buried. In more recent centuries, entire neighborhoods and ancient streets were simply built over, while some structures were deliberately buried or hidden due to religious or political shifts.

4. The Evolution of Streets and Modern Construction

As new road systems and neighborhoods were developed, city planners made the choice to build over existing structures rather than excavating old layers. This trend continued even into the 20th century. Today, archaeological sites are discovered whenever new subway lines or major building projects are planned, which has led to a deeper understanding of the “lasagna effect” of layers.

Why the “Lasagna” Metaphor?

This metaphor perfectly captures Rome’s unique structure, where each layer of history is piled on top of the last, similar to the layers of pasta, sauce, and cheese in a lasagna. The nickname celebrates Rome’s layered heritage, from imperial monuments to medieval basilicas and Renaissance palaces, all coexisting, sometimes right beneath modern-day streets and buildings.

This depth of history makes Rome one of the richest archaeological cities in the world, offering new discoveries with each excavation or construction project. Walking through Rome, you’re often treading over hidden parts of history, making it a living museum of human civilization across millennia.