Calçada Portuguesa

Calçada portuguesa is made by hand: white limestone and black basalt cut into small cubes and set in sand by calceteiros working on their knees with a hammer, laid to a drawn pattern. The technique in its modern form dates to the 1840s, when prisoners under Lieutenant-General Eusébio Furtado paved the castle yard and then, in 1848, the Rossio in a wave design called mar largo. It spread from there across Portugal and the empire - Copacabana's promenade in Rio is the best-known descendant. Patterns range from simple bands to ships, compass roses, animals, coats of arms and the mermaid and caravel motifs of the coast. It is also contested: the stone is slippery when wet or polished by footfall, it is hard on ankles and impossible for wheelchairs, and cities argue continually about repairing it versus replacing it with something safer. Calceteiro is a trade in decline, with schools set up to keep it.

What you actually see

• The technique - hand-cut limestone and basalt cubes set in sand to a drawn pattern.
• The 1848 Rossio - the mar largo wave that launched the style.
• The motifs - ships, compass roses, animals and arms across squares nationwide.
• The argument - beauty against a genuinely slippery and inaccessible surface.

When to go

Year-round, wherever you walk. It photographs best in low sun, which brings out the pattern; wet stone is dangerously slick.

Honest expectations

Genuinely slippery when wet or worn, and a common cause of falls - shoes with grip matter. Impassable for wheelchairs and hard on anyone unsteady. Repair backlogs leave loose and missing stones. The trade is shrinking and skilled repairs are scarce.

Nearby

Rossio in Lisbon holds the original mar largo; every Portuguese town square has its own version.