Fish

Since opening in 1981, the National Aquarium in Baltimore has proved a popular tourist destination, an educational excursion, and a great refuge from the heat in summer months. Many people don’t know, however, that there was a smaller, more modest National Aquarium in D.C. for years before the one in Baltimore popped up.

Washington D.C. has its hidden gems, but none perhaps as hidden as the long-gone and long-forgotten carp ponds of the National Mall, a main attraction in the District for close to three decades. But you’ve probably never heard of them, and the U.S. government is happy about that.