The Acquario Civico di Milano, located at Via Gerolamo Gadio 2 on the edge of Parco Sempione, is one of the oldest continuously operating public aquariums in Europe. It was built in 1906 as the centerpiece of Milan's International Exposition — a world fair that also celebrated the opening of the Simplon Tunnel connecting Italy to Switzerland. Of the entire sprawling Expo complex, the aquarium is the sole surviving structure, making it not just a natural history institution but an irreplaceable piece of Milan's urban memory.
The building itself is a textbook example of Italian Liberty architecture — the local inflection of Art Nouveau that flourished in Milan in the early twentieth century. Designed by Sebastiano Locati, the façade is richly decorated with sculpted sea creatures, glazed majolica tiles in deep greens and blues, and sinuous floral motifs that blur the boundary between architecture and marine biology. A frieze of Neptune-like figures and writhing fish runs along the upper cornice, while the interior retains its original iron-and-glass structure. The building was designated a protected cultural monument, which has preserved its ornamental detail in near-original condition. The aquarium also houses a hydrobiological research station — the Stazione Idrobiologica — which has conducted freshwater and marine research continuously since the facility opened.
Inside, visitors move through a series of illuminated tanks displaying Mediterranean coastal species, Adriatic fish, freshwater inhabitants of Italian rivers and lakes, and tropical specimens. Among the permanent residents are moray eels, grouper, cuttlefish, sea horses, and large rays. The exhibits are arranged thematically by ecosystem rather than purely by taxonomy, giving visitors a sense of habitat context. The relatively compact scale of the aquarium — compared to modern mega-facilities — creates an intimate atmosphere that allows for close observation, and the low lighting and the quiet gurgling of the tank filtration systems give the rooms a contemplative, almost chapel-like quality.
Admission is modestly priced and the aquarium is included in the YesMilano City Pass. The site is easily reached on foot from Castello Sforzesco, just a five-minute walk through Parco Sempione. Tuesday through Sunday opening hours apply; the aquarium is closed on Mondays. It is particularly well suited for visits with children, but the architectural exterior alone rewards any visitor with an interest in early twentieth-century decorative arts. Budget at least an hour inside, and take time to examine the façade details before entering — the ceramic tile work on the exterior is among the finest surviving examples of Liberty ornamentation in Milan.
