7 Best Sights in Estremadura and the Ribatejo, Portugal

For a close look at this storybook castle on a craggy island in the Tagus River, take the 1½-km-long (1-mile-long) dirt road leading down to the water from the N3. The riverbank in this area is practically deserted, making it a wonderful picnic spot. From here, a small motorboat will ferry you across (€4 round-trip) to the castle and its modern Templar Interpretation Center. For a more leisurely river cruise, book ahead to board a larger vessel (€6) at the quay just downstream in the village of Tancos. The sight couldn't be more romantic: an ancient castle with crenellated walls and a lofty tower sits on a greenery-covered rock in the middle of a gently flowing river. The stuff of poetry and legends, Almourol was the setting for Francisco de Morais's epic novel Palmeirim da Inglaterra (Palmeirin of England), about two knights fighting for a princess's favor. Your boat ticket includes admission to the castle and its small museum.

The outer walls of the fine medieval castle enclose the entire town, and it's great fun to walk their circumference, viewing the town and countryside from above—but take great care as there is no inner wall or railing for the most part. Extensively restored after suffering severe damage in the 1755 earthquake, the multitower complex has both Arabic and Manueline elements. Most of the keep is now a pousada.

Atop a hill rising from the Old Town is this remarkable UNESCO World Hereitage Site. You can drive to the top of the hill or hike for about 20 minutes along a path through the trees before reaching a formal garden lined with azulejo-covered benches. This was the Portuguese headquarters of the Knights Templar, from 1160 until the order was forced to disband in 1314. Identified by their white tunics emblazoned with a crimson cross, the Templars were at the forefront of the Christian armies in the Crusades and during the struggles against the Moors. King Dinis in 1334 resurrected the order in Portugal under the banner of the Knights of Christ and reestablished Tomar as its headquarters. In the early 15th century, under Prince Henry the Navigator (who for a time resided in the castle), the order flourished. The caravels of the Age of Discovery even sailed under the order's crimson cross.

The oldest parts of the complex date to the 12th century, including the towering castle keep and the fortresslike, 16-sided Charola, which—like many Templar churches—is patterned after the Church of the Holy Sepulchre in Jerusalem and has an octagonal oratory at its core. The paintings and wooden statues in its interior, however, were added in the 16th century. The complex's medieval nucleus acquired its Manueline church and cluster of magnificent cloisters during the next 500 years. To see what the Manueline style is all about, stroll through the church's nave with its many examples of the twisted ropes, seaweed, and nautical themes that typify the style, and be sure to look at the chapter house window, one of the most photographed in Europe.

Dedicated to "Saint Mary of Victory," this UNESCO World Heritage Site was built to commemorate a decisive Portuguese victory over the Spanish on August 14, 1385, in the Battle of Aljubarrota. In this engagement the Portuguese king, João de Avis, who had been crowned only seven days earlier, took on and routed a superior Spanish force. In so doing he maintained independence for Portugal, which was to last until 1580, when the crown finally passed into Spanish hands. The heroic statue of the mounted figure in the forecourt is that of Nuno Álvares Pereira, who, along with João de Avis, led the Portuguese army at Aljubarrota.

The monastery, a masterly combination of Gothic and Manueline styles, was built between 1388 and 1533. Some 15 architects were involved in the project, but the principal architect was Afonso Domingues, whose portrait, carved in stone, graces the wall in the chapter house. In the great hall lie the remains of two unknown Portuguese soldiers who died in World War I: one in France, the other in Africa. Entombed in the center of the Founder's Chapel, beneath the star-shape, vaulted ceiling, is João de Avis, lying hand in hand with his English queen, Philippa of Lancaster. The tombs along the south and west walls are those of the couple's children, including Henry the Navigator. Perhaps the finest parts of the entire project are the Unfinished Chapels, seven chapels radiating off an octagonal rotunda, started by Dom Duarte in 1435 and left roofless owing to lack of funds. Note the intricately filigreed detail of the main doorway.

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.

Over the centuries the crown, church, and nobility have contested the ownership of the Mafra National Palace and Convent, 8 km (5 miles) southeast of Ericeira. From the 17th through 19th centuries this was a favorite residence for the Portuguese court. In 1711, after nearly three years of a childless union with the Hapsburg queen, Maria Anna, a despairing King João V vowed that should the queen bear him an heir, he would build a monastery dedicated to St. Anthony. In December of that same year, a girl—later to become queen of Spain—was born; João's eventual heir, José I, was born three years later. True to his word, King João V built an enormous monastery, which still looms above the small farming community of Mafra. The original project—entrusted to the Italian-trained German architect Johann Friedrich Ludwig, invariably known in Portugal as João Frederico Ludovice—was to be a modest facility that could house 13 friars. Construction began in 1717 and continued until 1755, with the final result being a rectangular complex containing a monastery large enough for hundreds of monks as well as an imposing basilica and a grandiose palace that has been compared to El Escorial outside Madrid, Spain. The numbers involved in the construction are mind-boggling: at times 50,000 workers toiled. There are 4,500 doors and windows, 300 cells, 880 halls and rooms, and 154 stairways. Perimeter walls that total some 19 km (12 miles) surround the park.

The highlight of any visit to the monument is the magnificent baroque library: the barrel-vaulted, two-tiered hall holds almost 40,000 volumes of mostly 16th- through 18th-century works and a number of ancient maps. Protection from insects is provided by bats, which slip into the room at night through tiny holes that were bored through stone under the windows for the purpose. The basilica contains 11 chapels and six organs—used simultaneously for splendid concerts at 4 pm on the first Sunday of every month except January and February—and was patterned after St. Peter's in the Vatican. When you're in the gilded throne room, notice the life-size renditions of the seven virtues, as well as the impressive figure of Hercules, by Domingos Sequeira. Guided visits may be booked in advance at an additional cost of €6 per person.

One of Portugal's most picturesque beaches is framed by steep cliffs and a fast-flowing stream. Strong tides can make the ocean here hazardous, but there are lifeguards on duty in summer. The beach itself bustles with sporting activity, and at night the village bars are lively. Some local houses have an alpine look, thanks to the availability of pine from the forests that blanket the Leiria region—which also makes for lovely fresh air. Amenities: food and drink; lifeguards; parking (no fee); showers; toilets; water sports. Best for: sunset; surfing; swimming; walking.