The limestone promontory at Ponta da Piedade drops twenty metres into the Atlantic in stacked ochre columns, their bases hollowed into sea caves that take ten thousand years to carve. The rock is a Middle Miocene bioclastic formation — fossilised coral, shell, and algae compressed into sediment fifteen million years ago, then tilted and fractured by tectonic shift. Wind and wave have done the rest. By the sixteenth century, Portuguese navigators sailing west from Lagos used the headland as their last visual fix before the open ocean; today the same cliffs anchor a yacht tour Lagos itinerary that threads arches, tunnels, and pocket beaches only accessible by sea. Lagos harbour became the Algarve's principal maritime hub under Prince Henry the Navigator, who established a shipyard and navigation school here in the 1440s. Caravels bound for the African coast and the Atlantic islands departed from the same anchorage that now shelters the modern Marina de Lagos, where fiberglass hulls have replaced oak and lateen canvas. The town's maritime identity persists — fishing cooperatives still operate from the eastern quay, and the smell of grilled sardines drifts across Passeio dos Descobrimentos at midday. The coast itself, a ten-kilometre stretch from Meia Praia to Ponta da Piedade, reveals a geology textbook in cross-section: erosion windows, blowhole chimneys, and wave-cut platforms that trap tidal pools thick with anemones and blennies. Boat operators run morning departures from the marina between April and October, when the Atlantic calms and visibility sharpens. The most frequented route follows the western shoreline to Ponta da Piedade, entering the grottoes at low tide when headroom permits passage beneath natural bridges. A longer circuit continues west to Praia do Camilo and Praia Dona Ana, both beaches hemmed by vertical rock walls that glow rust-orange in afternoon light. The eastbound alternative cuts across open water toward Benagil, twenty kilometres up the coast, where a collapsed sea cave forms a circular skylight above a sand floor — a feature that appears on every Algarve postcard but remains inaccessible except by watercraft. The vessels vary: rigid inflatables for speed, catamarans for stability, traditional wooden craft for a slower cadence. All share the same departure point and the same window of reliable sea conditions, making timing and vessel choice the twin variables that define the experience.