TAP, the Portuguese airline, now offers free stopovers in Lisbon on flights from the US to other destinations in Europe. That’s too good a deal to resist, so on our recent trip to France we took advantage of a short add-on in one of our favorite cities. Here’s how you can do it, too.

Begin on Praca dos Restauradores at the Tourist Office, for a map and bus route info, then walk through the large Rossio square, stopping at a sidewalk cafe for coffee and to get geographical bearings with the map.

Day 1 – The River and Alfama
Head to the grand arcaded Praca do Comercio, at the river, for a boat ride on the Taugus. Climb through the steep streets and stairs of the Alfama, stopping at the Se (cathedral) and Largo Santa Luzia, a garden belvedere with azulejo (tile) panels and views over the Alfama rooftops to the river. Continue climbing through narrow streets to Castelo de Sao Jorge and the old bairro (neighborhood) of Santa Cruz for more sweeping city views. In the castle’s vaulted interior, multi-media exhibits show the history of the city and fort, occupied in turn by the Phoenicians, Romans, Visigoths and Moors. In the evening, take in a fado show at Club de Fado, just as popular with locals as it is with tourists.

Day 2 - Belem Monastery and Museums
From Praca do Comercio take the tram to Belem to visit Jeronimos, one of the three major monasteries in Portugal. Admire the church’s soaring architecture and stone carving, and the outstanding double cloister with delicately carved stone tracery; Jeronimos is a UNESCO World Heritage Site.

See the Coach Museum in the grand 18th-century royal riding school, filled with the swirling rococo of grand coronation and ambassadorial coaches. The large monument overlooking the river like a huge ship commemorates Prince Henry the Navigator, who inspired Portugal's age of discovery in the 1400s.

For the museum-minded, this is your neighborhood. The Museu de Marinha shows Portugal's love affair with the sea with outstanding collections that include a royal barge. The Museu Nacional de Arqueologia holds some of the country's most ancient artifacts, from prehistoric stone carvings to a collection of rare gold jewelry. The Museu Colecção Berardo opened in 2007, immediately ranking alongside the Guggenheim in Venice and other modern art museums worldwide. A 20-minute walk along the river is the Torre de Belem, an impressive tower built in 1515.

Back in the city center, take the Santa Justa elevator from the lower city to the Barrio Alto, central Lisbon’s other hillside neighborhood in the evening, choosing any of its restaurants for a typical Portuguese dinner.

Day 3 - Queluz and Sintra
Take the train from Rossio station to Queluz and Sintra, where Portugal's royalty lived. Queluz, consists almost entirely of the candy-colored baroque palace and the sprawling gardens that surround it. Remember all those carriages you saw yesterday? Picture them here, as footmen scurry to hand down ladies in voluminous skirts arriving for a royal ball.

In Sintra, Palacio Nacional is easy to spot by its two giant chimneys. Inside, the tile work is outstanding. While this palace has more history and some great stories of royal family intrigue, another highly unimportant palace is more fun. Quinta da Regaleira is a fanciful group of buildings set in landscaped gardens with grottos and a warren of underground passages reached by a spiral staircase into a 200-foot-deep dry well.

It’s impossible to take Pena Palace, high on a hill overlooking Sintra, seriously, but it was a real palace, built by a royal couple in the height of the Victorian era. True to its period, it has a bit of every architectural style since Medieval, including parapets, Gothic towers, cupolas, Moorish arches, onion-shaped domes, all topped off with Portugal’s own unique style of fanciful stone carving, called Manueline. The surrounding Pena Park is a garden of camellias and rare plants.

Back in Lisbon, go left out of Rossio Station and walk up the tree-lined Avenida Liberdade until you reach the base of the Elevador da Gloria, an old fashioned train that climbs the steep hill to the Barrio Alto. Step into the park at the top for a glorious view of the castle bathed in the rosy sunset light, then browse among the neighborhood’s restaurants for dinner.