The Oceanographic Museum of Monaco is a monument in itself. First, thanks to its incredible architecture: built into the side of a cliff, it rises 85 meters above the Mediterranean. Second, because it is a pioneer in the exploration of the marine world. Created in 1910, at the instigation of Prince Albert I, it continues its scientific and artistic mission today. These two aspects give rise to monumental construction projects and large-scale exhibitions. This documentary revisits the incredible history of this unique site and reveals the many challenges of its construction.