The Shedd Aquarium is part of Chicago's Museum Campus (along with the Field Museum and the Adler Planitarium). John G. Shedd, a protege of Marshall Field, gifted the aquarium to the city. It was the first inland aquarium with a permanent salt water fish collection and,at one time, was the largest aquarium in the world. Construction began in November of 1927 and was opened in May of 1930. A custom made railroad train, named the Nautilus, with 20 tank cars, made eight round trip voyages from Key West, Florida, in order to transport the fish and saltwater to Chicago. In 1971, one of the aquarium's most popular exhibits, the 90,000 gallon Caribbean Coral Reef, was added. At the same time, the first research vessel was purchased. By 1987, the Shedd Aquarium was placed on the National Register of Historical places.