The dune belt south of the Tagus is younger than most of Lisbon's monuments — much of the Costa da Caparica sand ridge has shifted position within the last three centuries, redrawn by Atlantic swell and prevailing north-westerlies. The coastline here begins where the river ends. Costa da Caparica runs roughly 25 kilometres south from the Tagus estuary mouth, backed by the Arriba Fóssil da Costa da Caparica, a fossil cliff protected as a paisagem protegida since 1984. Its ochre and rust-red strata are Miocene and Pliocene sediment, laid down when this stretch lay beneath a shallow sea. Fishermen from the Algarve settled the beaches in the eighteenth century, working the arte xávega — a hauling net drawn ashore by oxen, later by tractor. A handful of crews still practise it. Lisbon quad bike hire operators now run the same sand flats those nets once crossed. What gives the area its present character is contrast. Twenty minutes over the 25 de Abril Bridge from Praça do Comércio, the city's tiled façades give way to pine, eucalyptus and open dune. The Paisagem Protegida da Arriba Fóssil covers about 1,570 hectares. Within it sit the Lagoa de Albufeira, a coastal lagoon that opens and closes to the sea by season, and the Capuchos convent, founded in 1558. Trails thread between them: firebreak tracks, agricultural lanes, packed sand corridors below the cliff line. Guided quad and buggy routes use these existing ways rather than cutting new ones, a condition of operating inside protected landscape boundaries. The Atlantic Coast quad tour has become the standard way independent riders read this geography at speed. Sightlines matter more than distance. From the cliff-top at Fonte da Telha the view carries north to Cabo Espichel's lighthouse promontory and, on clear mornings, the outline of Sintra's hills across the estuary. Below, wind farms and the Meco surf breaks mark the southern end of the ridge. Seen against Lisbon landmarks — Jerónimos, Belém, the Alfama terraces — this coast reads as the city's unbuilt margin, the place its geology stays visible. Buggy and quad routes here trade tiled interiors for exposed rock, salt spray and pine resin. The lisbon quad bike hire tour has grown from an off-season curiosity into a year-round fixture of the Setúbal peninsula's visitor economy, and the cliff itself continues to erode by measurable centimetres each winter.