The National Aquarium – also known as National Aquarium in Baltimore and formerly known as Baltimore Aquarium – is a non-profit public aquarium located at 501 East Pratt Street on Pier 3 in the Inner Harbor area of downtown 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 visitors and is the largest tourism attraction in the State of Maryland.