Tróia Peninsula

Tróia is a spit of sand about eighteen kilometres long enclosing the mouth of the Sado, with ocean beach on one side, the estuary channel on the other, and dunes and umbrella pine along its length. At the northern tip are the Roman ruins of Caetobriga, one of the largest fish-processing complexes known in the Roman world: rows of stone tanks where fish was salted and garum, the fermented fish sauce that Rome ran on, was produced for export, along with a bath house and a mausoleum. The channel between Tróia and Setúbal holds a resident bottlenose dolphin population, and boats cross it constantly - the ferry, which takes cars and passengers, is the short way in. The northern end is developed with a marina, golf and apartment towers built in the 1970s; south of that the spit is largely dune, protected, and empty.

What you actually see

• The Roman complex - salting tanks from one of the largest known garum works.
• The spit - eighteen kilometres of dune and pine between ocean and estuary.
• The dolphins - the resident bottlenose population in the channel.
• The contrast - 1970s resort development at the tip, protected dune south of it.

When to go

May to September. A day, including the ferry from Setúbal. The Roman ruins keep limited hours - check before crossing.

Honest expectations

The ferry queues in summer with cars, and the road route around is long. The resort end is dominated by 1970s towers. Beaches have no facilities away from the north. Dolphin sightings from the ferry are luck, not a given.

Nearby

Setúbal is across the water; Comporta and the Alentejo beaches run south.