The circular building that would become the Aquarium in Battery Park was constructed in 1807 as a fort. It would become an auditorium, Castle Garden, and was later the reception building for immigrants until Ellis Island assumed those duties in 1891. The Aquarium was established in 1896 and the structure was used in that capacity until 1941. This white border postcard provides no publisher data and the postmark is difficult to read, but it may have been mailed in 1916. On the back:
AQUARIUM IN BATTERY PARK
The Aquarium, on the Battery sea-wall, contains 122 glass tanks, which are filled with the finest collection of living fishes ever displayed. Originally this building was called Fort Clinton, afterwards as Castle Garden, a noted amusement resort. For a great many years it was the immigration depot. When the immigration depot was moved to Ellis Island the old Fort was converted into an aquarium. It is visited annually by 2,000,000 people.