Hawai’i Volcanoes National Park, Hawai’i
Tourism to the active volcano at Kilauea on the island of Hawaii took off when it became a national park in 1916, just a few weeks before the National Park Service was created. A popular early tourist activity was walking out onto the hard crust of an active lava flow and using a stick to thrust their postcards into a fissure and scorch it before mailing. Even in the age of Twitter and Facebook, postcards remain a popular way to let people know you were really there—and prove it with a postmark!