Walking through Cartagena's Barrio del Foro Romano feels like stepping into a perfectly preserved slice of ancient life. This isn't your typical archaeological site where you squint at scattered stones trying to imagine what once stood there. Here, entire Roman buildings emerge from beneath the modern city streets, complete with colorful frescoes still clinging to 4-meter-high walls.

The site centers around what was once a major Roman street called the Decumano, connecting the forum to the port area. You can actually walk along sections of this ancient road, laid out in the 1st century but rebuilt in the 4th century when Cartagena became the capital of the Carthaginense province. There's something oddly moving about following the same path Roman merchants took two thousand years ago.

What strikes me most are the thermal baths on Calle Honda. The Romans didn't do things halfway – these baths had hot rooms, cold rooms, saunas, and even a gymnasium for working out. The complex stayed active until the 6th century, adapting and evolving as the empire changed around it. During excavations, archaeologists found a beautiful marble cornucopia that probably decorated a statue in the exercise area.

The atrium building next door tells a different story. Built around a Tuscan-style courtyard, it likely served as headquarters for one of the Roman guilds. The painted walls here are extraordinary – not just decorative borders, but complete pictorial cycles that once adorned banquet halls where guild members gathered for religious feasts.

Then there's the Isis sanctuary, tucked between the other buildings. This Egyptian goddess had quite a following in Roman Cartagena, and you can still see the underground cisterns where sacred water was stored for mysterious ceremonies. Fragments of Isis statues found here show how cosmopolitan this port city really was.

The museum opened in 2021 displays the most significant finds, and an audio guide helps decode the more subtle details. But honestly, the buildings themselves tell the story. Standing in these rooms, looking up at frescoed ceilings and walking across original Roman floors, you get a sense of daily life that no textbook can convey. The site won Spain's National Prize for Restoration and Conservation in 2013, and after visiting, you understand why.

This hidden neighborhood spent twenty centuries buried beneath Cartagena's streets. Now it offers one of the most complete pictures of Roman urban life you'll find anywhere in Spain.