Our visit takes us to the Alentejo region east of Lisbon, a rural area of fortresses, castles and palaces, centuries-old city walls, villages of whitewashed buildings, cobbled streets and churches lined with gold. Nothing happens quickly here and lunches and dinners, washed down with the region's fine blended wines, dictate the rhythm of life. The countryside is surprisingly green, plantations of cork and olives masking the desert-dry red soils.
At Marvao, an impregnable fortress on top of a granite escarpment near the Spanish border, the population has dwindled from about 1000 to 100. "It's like a ghost town in winter. It's sad," says Maria, our guide. It's far from quiet in high summer, of course, as tour buses climb the narrow road that clings to the escarpment. Tourists clamber up the cobblestone streets, past tascas and the aroma of bread baked in a centuries-old oven, to comb the castle.
Originally a Roman lookout post, Marvao's location just 13km from the Spanish border made it a bastion against invasion. It was called Eagle's Nest for a reason: even the doziest guard couldn't miss the slightest movement on the plains.
Barely a cannon ball's range away is Castelo de Vide, an important link in the chain of border outposts whose role was to protect Lisbon from invasion. With easy access to water and agricultural land, the town thrived commercially from the 14th century, when about 4000 Jews drifted here to escape persecution in Spain.
All went well until King Dom Manuel I, under pressure from Spain, ordered their expulsion in 1496. Doorways on many houses are still etched with crosses, used as a mark of suspicion during the Inquisition. There are no Jews left in Castelo de Vide, our guide tells us, but hidden synagogues, exposed when houses were renovated, are open to view. As impressive as the castle-topped towns of the Spanish border are, the town of Elvas, 50km south, is military-buff heaven. The walled fortifications, bastions and moats protecting the town were started by the Romans and extended by the Moors. Then, from the 1600s, the Portuguese got to work. The star-patterned walls, based on Dutch military thinking, are the biggest bulwark fortifications in the world and a World Heritage site.
In the heart of Alentejo is the main town, Evora. Here is Portugal's best-preserved Roman temple - 14 granite columns marking three sides of the 2nd-century temple, and the remains of Roman baths can be viewed inside the civic building. The cathedral presides over the town square, where examples of eccentric Manueline architecture are found on many buildings.
But the town's most affecting architecture is human. In the Church of Sao Francisco is the Chapel of Bones - the walls lined with skeletons of commoners buried outside the city walls. Spanish priests dug up the bodies in the early 1600s to build a memorial to man's mortality and equality. Our guide, Angela Fernandes, says the monument demonstrates that, rich or poor, the same fate awaits us all. Above the entrance are the words: "We bones here, for yours await."
* Geoff Cumming travelled as a guest of Emirates Airlines and Tourism Portugal.