Baixa, Lisbon

1 November 1755

The earthquake struck at about 09:40 on All Saints' Day, with the churches full; the fires that followed burned for days and the tsunami came over the riverfront onto the low ground where the palace, the customs house and the medieval lower town stood. This was the ground that suffered most, because it was river silt, and it is the ground Pombal chose to rebuild first. Sebastião José de Carvalho e Melo, later Marquis of Pombal, the king's chief minister, is credited with the order to bury the dead and feed the living, and then with the plan: the medieval streets were not to be rebuilt, the whole lower town would be cleared and laid out again on a grid.

Manuel da Maia, Eugénio dos Santos, Carlos Mardel

The chief engineer Manuel da Maia offered the king several options, from rebuilding as before to abandoning the site; the one chosen was the grid, drawn up by Eugénio dos Santos and Carlos Mardel. Streets run straight from the Rossio to the river and are crossed at right angles by narrower ones; each was assigned a trade, which the names keep, Rua dos Sapateiros for the shoemakers, Rua dos Correeiros for the saddlers, Rua da Prata and Rua do Ouro, now Rua Áurea, for the silver- and goldsmiths. The three main streets, Augusta, Prata and Ouro, run from the Rossio to Praça do Comércio; Rua Augusta is the pedestrian spine.

The façades were standardised so that the whole district could be built from prefabricated parts by different contractors and still look like one design, and the façade you see on one block is the façade on every block.

The gaiola pombalina

Inside each building is the gaiola, the cage: a timber lattice of diagonal braces built into the masonry walls and floors, designed to flex in an earthquake and hold the building up if the stone fell away. Wikipedia calls the result one of the first examples of earthquake-resistant construction, and the story that troops were marched around models to test them is part of the district's founding legend. Party walls were carried above the roofline to stop fire jumping from one block to the next.

The system was tested in the small quakes of the following two centuries and has not faced another 1755; the buildings are eighteenth-century timber frames behind their stone, which is why the fire of 1988 on the Chiado slope was the disaster it was. The district went onto Portugal's UNESCO tentative list in 2004, with the note that it stood above the comparable post-disaster rebuilds of Edinburgh, Turin and London.

Start in the Rossio, officially Praça Dom Pedro IV, the square with the wave-pattern pavement, the column with the king on top, the fountains and the Teatro Nacional D. Maria II across the north side; the ginjinha hatch on the corner of Largo de São Domingos, a bar the size of a cupboard, sells the sour-cherry liqueur in a shot glass at any hour it is open. Praça da Figueira, the market square east of it, has the equestrian statue of João I and the view up to the castle. Walk south down Rua Augusta, the pedestrian spine, with the Santa Justa Lift tower rising on your right after two blocks off Rua de Santa Justa; it is closed, so photograph it and carry on.

Rua dos Correeiros, parallel one street east, has the Roman bath-house at number 9 under the Millennium bcp bank, which you should have booked. The MUDE design and fashion museum on Rua Augusta itself is on the grid, and its own site returned an error when we read it, so its hours and price are not stated here. At the bottom, the Arco da Rua Augusta has its door on the street side, €5, 10:00 to 19:00, and the square and the river are through it.

• Rossio and Largo de São Domingos (ginjinha): 15 min
• Praça da Figueira: 5 min
• Rua Augusta south, Santa Justa tower on the right: 10 min
• Rua dos Correeiros 9, Roman baths (booked): 45 min
• Arco da Rua Augusta, €5: 30 min; Praça do Comércio and the river steps: 15 min

Under the Millennium bcp building at Rua dos Correeiros 9 is the best-kept surprise on the grid: the remains of a Roman fish-salting works and, above them, a bath-house of the third century AD with a polychrome mosaic in the cold room, the frigidarium, found when the bank rebuilt its headquarters in the 1990s and now run by the Fundação Millennium bcp as a free-standing archaeological site. The mosaic's borders run through knots, spindles, guilloche and a swastika meander, and it was conserved from August to December 2017 after salt crystallisation from the damp had begun to lift it. Visits are Monday to Saturday from 10:00 to 12:00 and from 14:00 to 17:00, closed on Sundays and holidays, by reservation through the foundation's booking system, confirmed in business hours, in groups of up to twelve including the guide.

The foundation's page prints no price, so we print none; other listings call it free, and we leave that to the foundation to confirm at booking. It is the one thing in the Baixa to book before you arrive.

No official crime figure is published for the district, so we quote none. Baixa is a busy shopping and transport district, and its problems are the ones such districts have: pickpockets on tram 28, which crosses the grid on Rua da Conceição and is where the city's professionals work; the men on Rua Augusta who offer sunglasses and then, quietly, something else, which a shake of the head ends; and restaurant terraces on the pedestrian street that charge for the couvert the moment you touch it. Violence is not a reported problem.

At night the grid is lit and busy until the restaurants close, quieter after midnight when the crowd is up in the Bairro Alto or down at Cais do Sodré, and never empty on Rua Augusta. The tourist police station is in Palácio Foz on Praça dos Restauradores at the north end of the grid, the emergency number is 112, and the safety and scams page has the rest.

• Tram 28 on Rua da Conceição: bag in front, phone zipped
• Sunglasses sellers on Rua Augusta: a shake of the head
• Couvert on the terraces: charged if touched; send it back untouched
• Tourist police: Palácio Foz, Restauradores; emergency 112

It is the practical choice and the one with the fewest surprises: every Metro line touches the grid at Rossio, Restauradores, Baixa-Chiado or Terreiro do Paço, the airport is one change away, the Belém tram and the Cascais train are at the river end, and no street has a step. The trade is what a shopping district trades: chains where the trades used to be, a crowd under the window from 11:00 to 22:00 on Rua Augusta and the streets beside it, and rooms priced for the postcode. Rua da Prata and Rua dos Fanqueiros on the east side are quieter than Rua Augusta; the Rossio and Restauradores fronts are loud and central; the blocks nearest Praça do Comércio sleep earliest.

For a first visit of a few nights most people are happier one street up in Chiado, which has the same Metro and the evening on the doorstep; for a one-night stop with a suitcase, this is the place. The where to stay page compares all seven areas with walk minutes and noise. The rest of the Lisbon guide starts from the homepage.