Walking on Geodiversity: the Artistic Stone-Paved Sidewalks of Lisbon (Portugal) and Their Heritage Value

Sidewalks are not a trivial topic. They are a fundamental element of streets, the main public spaces in urban environments. In modern cities, paving materials are mostly artificial. In Portugal, stone-paved sidewalks are still prevalent and quite characteristic. Walking down a street, you do not need to lift your eyes off the ground to know you are in Portugal. In nineteenth-century Lisbon, a new type of pavement was introduced, the calçada portuguesa, the Portuguese artistic pavement mainly made with white and black limestone or basalt. This pavement is examined herein. More than simply highlighting its geological components, the different meanings and values of the calçada will be discussed from a semiotic perspective. It will also be debated how this geocultural heritage asset became key in shaping the city’s image. How it boosted Lisbon’s memorability, thus generating a strong sense of place among its inhabitants. So much so that these days the calçada patterns are everywhere, from table ware to post stamps, and even on socks. And yet, the long-term survival of the artistic pavement may be in peril. To ensure its preservation, the calçada portuguesa was recently included in the Portuguese Cultural Heritage list, a crucial step towards UNESCO world heritage status. However, in the document ratifying its newly attained status, the geological component of the pavement is mostly neglected. To maximize the conservation effort, the many meanings and heritage values of the calçada, namely the geological ones, should be actively involved, this work hopefully contributing to this end.