Jerónimos Monastery

If you see one building in Lisbon, make it this one. The Mosteiro dos Jerónimos was commissioned by King Manuel I at the start of the sixteenth century, on the riverbank at Belém where Vasco da Gama's crew had spent their last night ashore before sailing for India, and it was paid for largely by the extraordinary wealth that the new sea route to the East poured into Lisbon. The result is the purest statement of the Manueline style — Portugal's own late-Gothic flourish, in which pillars twist like ship's rope, doorways sprout coral, artichokes and seaweed, and the king's emblem, the armillary sphere, appears wherever a carver could fit it. The monastery was handed to the Hieronymite monks, who prayed here for the souls of the king and his navigators until religious orders were dissolved in 1834; it survived the 1755 earthquake that flattened much of the city, and with Belém Tower it was inscribed by UNESCO as a World Heritage Site in 1983. A visit has two halves. The church of Santa Maria de Belém is free and has its own entrance: inside, slender columns branch into a vaulted ceiling like palm trees, and near the entrance lie the tombs of Vasco da Gama and of Luís de Camões, the poet who turned the voyages into Portugal's national epic. The paid half is the two-storey cloister, a square of honey-coloured limestone carved so densely that every arch rewards a second look, with the old refectory and its tiled walls opening off it. Timed tickets sell out in busy periods and door queues can be long, so book the cloister online, come at opening on a weekday, and remember it is closed on Mondays.

The building is a sermon on empire, and it helps to know how to read it. The south portal, facing the river, is the showpiece: a soaring screen of niches and pinnacles by João de Castilho, with Henry the Navigator standing on a pedestal between the doors and the Virgin of Belém above. The west portal, where you actually walk into the church, shows King Manuel and his queen kneeling with their patron saints. Inside, the crossing vault spans an astonishing width without central support, and it is said to have ridden out the great earthquake of 1755 while much of Lisbon fell. The monastery has also just emerged from a conservation campaign that ran for some two decades, supported by the World Monuments Fund, so the stone is as clean and sharp as it has looked in living memory.

Working the visit: if you only have half an hour, the free church alone is worth it; slip in, see the tombs and the columns, and come back for the cloister another day. With a timed ticket, start in the cloister while it is quiet. Walk the lower gallery slowly, then climb to the upper level for the views across the courtyard and the best angle on the carving, and look for the simple tomb of the poet Fernando Pessoa, whose remains were moved here in the twentieth century. The refectory, lined with eighteenth-century azulejos, and the upper choir of the church, looking down the nave, complete the circuit. Allow an hour and a half for the full visit; add more if you want to see the National Archaeology Museum and the Navy Museum, which occupy the long wings of the same building and are ticketed separately.

Belém is a day out in itself, so plan around the monastery. Arrive by tram 15 or train from Cais do Sodré, or by taxi along the river. Do Jerónimos at opening, cross the gardens of Praça do Império to the Padrão dos Descobrimentos and walk the riverside to Belém Tower for your timed slot, then double back for custard tarts at Pastéis de Belém, a few doors from the monastery. Summer afternoons are the worst time to queue: tour groups arrive in waves from late morning, and the sun on the open square is fierce. In winter the light on the limestone in the late afternoon is lovely, but timed slots still go early. Note that the Lisboa Card covers the cloister but you still need to reserve a time.