We walked off straight to the Tower of Hercules, and I felt the weight of history before we even reached the base. This isn't just the oldest Roman lighthouse in the world – it's the only one still working, its lantern sweeping the Atlantic exactly as it has since somewhere between 40 and 80 AD, when pottery shards tell us it was first kindled.

The cornerstone bears an inscription offering the tower to Mars, but the real monument is to a Roman architect named Gaius Sevius Lupus, who traveled all the way from Aeminium – modern Coimbra in Portugal – to design this beacon. He built it on a 57-metre rock that rises from the sea, then lifted it another 55 metres into the sky. Thirty-four metres of that is pure Roman masonry, stones fitted so precisely they've held for nearly two millennia.

Climbing the 242 steps felt like ascending through layers of time – Celtic, Roman, and medieval graffiti carved into the stones by sailors who passed through across the centuries. The earliest written record comes from a historian named Paulus Orosius around 415 AD, when the tower was already ancient. Then silence for centuries until January 4, 1788, when King Carlos III authorized a restoration. Architect Eustaquio Giannini added twenty-one metres of neoclassical stonework that wraps the Roman core like a protective sleeve. You can see where the old ends and the new begins, but both are weathered now, both belong to the sea.

At the top, Atlantic wind whipped our hair as we looked out over Monte dos Bicos, where Iron Age rock carvings mark even older human presence on this headland. In 2009, UNESCO named the entire site a World Heritage treasure, recognizing what sailors have always known: some lights never go out.

In the afternoon we wandered the glazed galerías – entire buildings wrapped in white-painted glass balconies that make the city sparkle like crystal against the sea. We had lunch at A Mundiña – pulpo a la gallega so tender it melted, pimientos de Padrón where one in ten is spicy and perfect. We went to Riazor beach for a swim – city beach with real waves and zero tourists. The pros: authentic Galician soul with almost no cruise crowds. The cons: Atlantic water is cold, but that's why it feels alive.