3 Best Sights in Alcobaça, Estremadura and the Ribatejo

Like the monastery at Mafra, the Mosteiro de Alcobaça was built as the result of a kingly vow, this time in gratitude for a battle won. In 1147, faced with stiff Muslim resistance during the battle for Santarém, Portugal's first king, Afonso Henriques, promised to build a monastery dedicated to St. Bernard and the Cistercian Order. The Portuguese were victorious, Santarém was captured from the Moors, and shortly thereafter a site was selected. Construction began in 1153 and was concluded in 1178. The church, the largest in Portugal, is awe-inspiring. The unadorned, 350-foot-long structure of massive granite blocks and cross-ribbed vaulting is a masterpiece of understatement: there's good use of clean, flowing lines, with none of the clutter of the later rococo and Manueline architecture. At opposite ends of the transept, placed foot to foot some 30 paces apart, are the delicately carved tombs of King Pedro I and Inês de Castro.

The graceful twin-tiered cloister at Alcobaça was added in the 14th and 16th centuries. The Kings Hall, just to the left of the main entrance, is lined with a series of 18th-century azulejos illustrating the construction of the monastery.

Housed in an old winery just outside Alcobaça, the Wine Museum is the country's best showcase of antique implements and presses, dating from the 17th to 21st centuries. Guided tours are offered on the hour from 10 to 5 (except 1 pm); call ahead to check if the day's guide can do them in English (it is usually possible), and conclude with a wine tasting.

The perfect horseshoe-shape bay here, 12 miles west of Alcobaça, makes this one of Portugal's prettiest beaches, lapped by calm waters that are safe for children. The ample strand—patrolled by lifeguards so long as beach cafés are open—has fine, yellow sand (cleaned daily) and areas with sunshades for rent. Much of it is lined with well-preserved dunes; at its northern end, set back from the promenade, are elegant old homes in the typical Caldas style, restaurants, and many hotels. The beach is popular with local families, so don't come in high summer if you dislike crowds. Local companies offer boating and canoeing trips. Amenities: food and drink; lifeguards; parking (no fee); toilets; water sports. Best for: sunset; swimming; walking.