The Exploratorium is a museum in San Francisco whose stated mission is to change the way the world learns. It has been described by the New York Times as the most important science museum to have opened since the mid-20th century, an achievement attributed to "the nature of its exhibits, its wide-ranging influence and its sophisticated teacher training program." Characterized as "a mad scientist's penny arcade, a scientific funhouse, and an experimental laboratory all rolled into one," the participatory nature of its exhibits and its self-identification as a center for informal learning has led to it being cited as the prototype for participatory museums around the world.