Little squares of white stones had been painstakingly laid, with a border laid in black, although sometimes grey stones are used as well, and I learned that they are cobbles of limestone.

I was impressed to say the least, especially watching it being laid in the street, the men squatting on their haunches, deftly and accurately placing the squares, tapping them into place before moving on to the next one. I was also impressed when we had a broken water pipe under ours in the garden, and after the leak was repaired, all the calçada was replaced like the pieces of a jigsaw - you would never have known there had been a big hole in the ground the day before. What a brilliant idea I thought, repairs can take place with no ugly patching of different types of concrete or weeds growing in patches where repairs had failed.

What I didn’t know at the time (until I had tripped over a few times and twisted my ankle) was that they can be incredibly uneven - a brisk walk down a path that looks flat can have more dips and rises than a roller-coaster and it reminded me of lurching along after a few too many glasses of wine! And go to an old or steep town you will find the calçada is so ancient that it has become polished smooth by countless pairs of feet (or on roads, countless vehicles) where they have become dangerously slippery, especially when wet. If ladies are unwise enough to step out in stilettos, they run the risk of getting their heels stuck in the little gaps and coming to grief and wrecking the shoes at the same time. In some towns the little sidewalks are so narrow and uneven, or have some of the cobbles missing completely, that stepping off into the road to avoid them has worse consequences than a twisted ankle.

They apparently originated in Mesopotamia and were used extensively in Roman times. In the mid-1800’s the São Jorge Castle in Lisbon was a military base and the Lieutenant general ordered part of the stronghold to be paved with a zigzag design of black and white stones. The job was executed by the prisoners, making them the first - although involuntary - calceteiros. The pattern, although not there anymore, was a big success, and soon after, the Rossio square in the centre of the city received a similar treatment of a waved pattern of black and white limestone named ‘the wide sea’ (and it doesn’t take long for the pattern to make your eyes go weird). The 8712 square metres of pavement are now one of the best known examples of calçada Portuguesa in Portugal.

The idea spread, and all over Portugal there are streets and esplanades featuring some wonderful artwork, some are even themed into the most intricate of patterns and designs, whether it be a single statement piece, several metres of swirling repeated patterns, or cleverly put together geometric designs. The more complicated the pattern, the longer the work takes. For plain pavements, an artisan can create around 10 square metres a day, but if the pattern is more elaborate, only about 1 square metre a day is possible.

The future of calçada Portuguesa is uncertain, as there are several valid arguments to replace it with safer and easier alternatives, but it’s also an important piece of Portuguese heritage that hopefully will never disappear completely from the historical city centres.

But being a calceteiro takes a lot of patience, and bending over all day under the hot Portuguese sun isn’t easy. The long hours and low wages had reduced apprenticeships and thus new pavers. In 1986 the City Council of Lisbon established a special school to educate new calceteiros, and at that time the city was employing around 400 pavers to preserve and expand the calçada. Since the nineties the introduction of concrete and asphalt pavements had reduced the required number of craftsmen drastically, and the city still struggled to find enough students. Enough applied, but most were just looking for ways to earn a living rather than being passionate about the art and skill, and many dropped out when they found the work to be too hard or when other possibilities appeared. Since the beginning of the school, only 224 students received the certificate marking them as professional stone pavers.

But thumbs up to the very skilled artisans who created such wonderful ways to decorate what would otherwise have been very dull and boring open spaces, but thumbs down to the death-trap holes when they fail to be repaired, unfortunately likely to be due to the lack of craftsmen available.