Do you know what a tide gauge is and what it is for?
Did you know that the Marégrafo de Cascais (1882) is the oldest in the world still operating in perfect condition?
The Marégraph of Cascais records allow to accurately measure, among other things, the altitude of mountains, the cartographic relief and to map the submerged territory with implications as varied but useful as the entry of a ship in the bar of an estuary or in aviation . But there is more: on the occasion of the tsunami that devastated part of the island of Samatra, Indonesia, on December 26, 2004, the Cascais Maregraph registered with absolute precision the phenomenon caused in the oceans by that devastating earthquake.
The Cascais Marégraph was one of the first European observatories dedicated to the study of currents and tides and is the only one that still works in perfect conditions throughout the world.
Built by A. Borrel, in 1887, in Paris, and connected to the oceanographic laboratory of King Carlos I, the Marégrafo de Cascais was installed in 1882 on a rock next to the fortress overlooking the bay of Cascais.