Lisbon, rebuilt

Jacaranda trees shade the small square in front of the Carmo ruins, a pocket of calm on the hill above the lower town, and under them a late Baroque fountain sits inside a stone porch carried on four pillars. That is the Chafariz do Carmo, built in 1771 to hand out water brought from the Águas Livres aqueduct through an underground gallery, the Galeria do Loreto; today it only decorates. The walk begins up here and ends at the river. It leaves the square by Calçada do Carmo, the lane that drops away towards Rossio. For now, stand with the fountain at your back: the roofless Gothic church fills the far side of the square.

Calçada do Carmo tips you downhill between tall houses, four minutes of slope with the lower town showing in glimpses ahead. At the bottom you come out beside Rossio station, whose Neo-Manueline front was designed by José Luís Monteiro in 1886 and 1887 and opened in May 1891; look for the two intertwined horseshoe doorways; behind them the trains arrive through a long tunnel dug under the city. Then the square itself. In 1848 the engineer Eusébio Pinheiro Furtado had Rossio paved in black and white waves, a homage to the sea crossed by Portuguese sailors. You have arrived when that rolling pavement is under your feet and the tall column stands ahead at the centre.

Rossio's north-east corner leaks into a smaller, plainer square, São Domingos, and the way there is two minutes along Rua do Amparo. One drink has been sold on this square since 1840: that year a Galician, Francisco Espinheira, opened A Ginjinha here, a tiny bar that pours the sour-cherry liqueur Lisbon calls ginja, and the custom has never moved on. The light changes too, from the open sweep of Rossio to a close, shaded space with the church set back along its edge. Its pale stone front, almost blank, is on your right as you come in.

Back across the waves of Rossio and into the grid of straight, narrow streets: Rua dos Sapateiros is the street of the shoemakers. At number 225 the Animatógrafo do Rossio opened as a cinema in 1907, and its Art Nouveau front of carved wood and two azulejo panels survives. The climb to the upper town takes nine minutes, up Rua do Carmo. In the early hours of 25 August 1988 a fire broke out in the Grandella department store on this street and spread through eighteen buildings; Álvaro Siza Vieira oversaw the rebuilding, mostly complete by 1999. You arrive at the top, the iron tower beside you and the Baixa's rooftops spread out below.

Chiado takes its name from a sixteenth-century poet, António Ribeiro, whose nickname meant "squeak"; his bronze statue has sat in the square up the hill since 1925. You brush the quarter's edge on Rua Garrett, its principal shopping street, then drop for nine minutes back into the Baixa. On 5 November 1910, a month after the Republic was proclaimed, every street down here that carried a monarchy name was renamed, and Rua da Prata, which runs parallel to Rua Augusta, only got its present name in 1910. The last stretch is a wide pedestrian street with the river light growing at its end, until a single stone arch closes it, its opening framing the square beyond.

Under the arch, and the city stops being streets. Two minutes, no more: a crossing, then the paved floor of Praça do Comércio spreads out ahead, yellow arcaded ranges on three sides and the Tagus filling the fourth. In the arcade on your left as you come through is Martinho da Arcada, a café founded in 1782 that Fernando Pessoa counted as his favourite. Out in the open the wind off the river reaches you for the first time on this walk. You are in place when the bronze horseman on his tall plinth is in front of you and the water glitters behind him.

A minute across the open stone to the water, and that is the walk. Off to your right, west along the bank, the waterfront runs on to Cais do Sodré as the Ribeira das Naus, the old boatyard: the second phase of its rebuilding opened in July 2014, restoring a dry dock, the Doca Seca, beside broad steps that lead down into the Tagus and that Lisbon treats as a river beach, though bathing is forbidden. You have come from a hilltop square to the edge of the estuary. Two marble columns stand at the head of a flight of steps that drop straight into the river; sit on them if the tide lets you.