The Marine Aquarium of the Mediterranean was named for the great naturalist Diacinto Cestoni, who died in 1718 at Livorno, the city in which he had opened a pharmacy. The building, extensively remodelled for the inauguration (June 20, 1937), had been previously occupied by a heliotherapy centre. Destroyed by bombing in 1943, it was rebuilt in 1950.

Between the early 1950s and the 80s, Mauro Sordi, long-time Director of the Aquarium, formed a collection, today named for him, consisting of showcases with prepared specimens of invertebrates and glass bottles containing various products. Closed for renovations in 1999, the aquarium was reopened in July 2010.

Today, the aquarium tanks host animal and plant species typical of Mediterranean waters and tropical seas. The first floor also houses temporary exhibitions, beautifully combining in one place, nature, history, science and art.