2 Best Sights in Estremadura and the Ribatejo, Portugal

Many travelers make a beeline for this 16th-century fort—which since 1903 has also served as a lighthouse—as the ideal vantage point for watching the waves that attract the world's best surfers. The structure also houses a small surf museum, whose displays include fascinating explanations of how the offshore Nazaré Canyon enables the waves to form.

On a hill just north of the city, Forte de São Vicente was the first of 152 redoubts built on the Duke of Wellington's orders to form three defensive lines between the Atlantic Ocean and the Tagus, to protect Lisbon from possible invasion by French troops. Since 2017, it has housed a small visitor center for these Lines of Torres Vedras, with fascinating displays such as a model of the system used to communicate between forts.