The Amoreira Aqueduct is the most photographed structure in Elvas and probably the most extraordinary thing in the Alentejo. Nearly seven kilometres long, with four tiers of arches reaching 30 metres high at its most dramatic stretch on the western approach to town, it was built specifically to allow Elvas to withstand a siege — and it did, repeatedly, through the Restoration War with Spain.
The best view is from the road that approaches Elvas from the south, where you pass directly beneath the highest section. There is no entrance fee, no railings, no interpretation — you simply walk under it. The aqueduct is still in working condition and still feeds the Fonte da Misericórdia in the old town. Allow an hour to walk a section properly and take photographs.