La Barceloneta and Torre del Rellotge

A stone pyramidal tower with four clock faces stands by a working fishing pier. When the harbor entrance moved farther out to sea, its navigation light went out, and the tower was preserved after the neighboring service buildings were dismantled. The clock installed in place of the light was originally intended for another port building, but remained here; harbor workers and passersby checked the time by it. Now, behind the tower, fish are unloaded and traded at the fish market.

When this tower was first lit in seventeen seventy-two, it stood at the very end of the western mole. Beyond it began the open sea. La Barceloneta was then a young neighborhood, built beside a growing harbor. On the mole, sailors showed their passports, underwent health inspections, and took a harbor pilot aboard, while the tower's light marked the entrance for ships. New piers have now appeared around it, and Barcelona's first lighthouse lies deep inside the harbor.

Twenty years later, the French astronomer Pierre Méchain turned this lighthouse into a survey marker. Revolutionary France was preparing to replace its many local measures with one common unit linked to the size of the Earth. The meter was defined as one ten-millionth of the distance from the pole to the equator. Méchain was assigned the southern half of the work: a chain of measurements from the city of Rodez to Barcelona; his colleague Jean-Baptiste Delambre led the northern half.

Measuring the entire route with a tape measure was impossible. The astronomers selected high, fixed points, formed triangles from them, and calculated distances from the measured angles. In Barcelona, these points were Montjuïc, the cathedral tower, one of the towers of the Ciutadella, and the harbor lighthouse. Its position was especially suitable: the stone tower stood right by the water and could be seen from different parts of the city. Working with a repeating circle, an instrument for very precise angle measurement, Méchain connected the Barcelona points to a chain of peaks running toward the Pyrenees and farther north.

The future standard depended on his precision, and precision was the trade through which he made a name for himself and supported his family. So a discrepancy of three arcseconds was a disaster for him. After determining the latitude first at Montjuïc and then from the roof of the Fontana de Oro hotel, he obtained results that did not match the distance between these points. Méchain searched for the error, stopped writing to his colleagues, and delayed the calculations. On top of that, war broke out between France and Spain: the border was closed, and the astronomer remained in Barcelona under surveillance.

Only in seventeen ninety-eight did he hand the calculations over to Delambre. An international commission checked them for half a year, and in June seventeen ninety-nine, a platinum meter standard was placed in the archive of the French Republic. Yet Méchain did not come to terms with the unfinished work. He returned to Spain to continue the measurement chain along the coast toward the Balearic Islands, and in eighteen oh four he died in Castellón de la Plana of malaria, which he contracted during the observations. Others completed the work, while the old lighthouse remained one of the preserved vertices of Barcelona's first geodetic network.

The light went out in nineteen oh four: the port moved its entrance far out to sea, and a new lighthouse on Montjuïc began guiding ships. The old tower was to be demolished to make room for trade. Several members of the port construction council insisted on preserving it; the surrounding service buildings were dismantled, but the stone pyramid was left.

In nineteen twelve, the clockmaker Josep Besses installed a clock with four faces in place of the light. It had been made for the new building of the Maritime Commandant's Office and was placed here temporarily, but it was never moved. Harbor workers and passersby checked the time by these faces, and the former lighthouse received its current name: Torre del Rellotge, the Tower of Clocks.

Now, a passage to the active fishing pier begins at its base. Since February two thousand twenty-five, the public has again been allowed here: behind the tower, fishers unload their catch, and an auction takes place at the new fish market. The stone lighthouse no longer shows ships the way; four clock faces remain where the lens stood, beside which Méchain included Barcelona in the measurement of the Earth.