Monument al Meridià verd

Monument al Meridià Verd stands on Ocata beach in el Masnou, a small coastal town in the Maresme region of Catalonia, just northeast of Barcelona. It is a modest stone monolith set right at the water's edge, marking the point where the so-called Green Meridian comes to an end.

What is the Green Meridian?

The Green Meridian is a symbolic heritage route that traces the historic 18th-century measurement of the Paris meridian — the scientific survey used to define the length of the metre as a unit of measurement. In Catalonia, the route (signposted as trail RT-6) runs north to south, starting near Coll de Pal in the Berguedà region, crossing the Montseny Natural Park and the Serralada Litoral range, and passing through towns such as Viladrau, Cànoves, la Roca del Vallès, Teià, Vilassar de Dalt and Premià de Dalt before reaching the coast at el Masnou. The monument on Ocata beach marks that final, southernmost point of the entire route.

What will you see at the monument?

The monument itself is an unassuming stone block facing the sea, standing just a few metres from the waterline. Its north-facing side carries inscriptions — facsimile reproductions of original scientific documents: the equations astronomers used in their calculations, and a map showing the full course of the meridian along with the triangulation points used to survey it. The monolith was installed in 2006 as a lasting marker of the geodetic measurements that led to the creation of the metric system.

How do you get there?

The monument sits directly on the seafront promenade of Ocata beach in el Masnou, so reaching it involves no climbing or lengthy hike — just a walk along the coastal boardwalk. El Masnou is served by the Rodalies R1 commuter line connecting Barcelona with the Maresme coast, making it an easy day-trip destination from the city. For those planning a longer outing, the monument works well as a natural starting or finishing point for the full RT-6 route heading inland toward Montseny and, further on, the Pyrenees.

When should you visit?

Since the monument sits in an open public space, it is accessible year-round and at any time of day. Early morning or late afternoon tend to be the most pleasant times to visit, when the beach is quieter and the light falls nicely on the stone's inscriptions. Spring and autumn suit a longer walk along el Masnou's promenade, while in summer the spot doubles as a resting point for beachgoers using the nearby swimming areas.

Why is it worth a stop?

The monument draws only a small number of visitors, but it holds particular appeal for anyone interested in the history of science — a physical trace of a European undertaking that changed how the world is measured. Unlike many historical monuments, this one commemorates neither wars nor rulers, but the astronomers and surveyors who plotted, metre by metre, the line connecting Maresme to Paris.

Frequently asked questions

Is there an entrance fee? No, the monument stands in a public space on the beach and can be viewed free of charge at any time.

How long does a visit take? Seeing the monument itself takes just a few minutes, but pairing it with a walk along el Masnou's promenade easily extends the visit to an hour or more.

Can you reach it by public transport? Yes, el Masnou has its own station on the Rodalies R1 line, from which it is a short walk to Ocata beach and the monument.

Is this the start or the end of the Green Meridian? It marks the southern end of the route — the Green Meridian runs from the mountains of Berguedà through Montseny down to the coast at el Masnou, finishing right at this monument.