The National Aquarium (formerly known as the National Aquarium in Baltimore) is a non-profit public aquarium located at 501 E Pratt Street in the Inner Harbor area of Baltimore, Maryland in the United States. Constructed during a period of urban renewal in Baltimore, the aquarium opened on August 8, 1981. The aquarium has an annual attendance of 1.5 million. The Aquarium holds more than 2,200,000 US gallons (8,300,000 l) of water, and has more than 17,000 specimens representing over 750 species. In 2003, the National Aquarium and the independent National Aquarium in Washington joined as one National Aquarium. The National Aquarium's mission is to inspire conservation of the world's aquatic treasures.