This very detailed and well-thought out set of online activities gives users the opportunity to listen closely to the particular sounds of the natural world. Based at the Exploratorium in San Francisco, this site was sponsored by the National Science Foundation and the National Endowment for the Arts. The site is divided into three sections: “At the Museum”, “Listening Guides”, and “Online Activities”. While the first section is intended for those who will make a trip to the Exploratorium, far-distant (and not-so-distant) users will find the other two sections the most helpful. “Listening Guides” includes testimonies and suggestions about listening to wildlife, urban environments, and even to build new experimental musical instruments. Users can learn about Bart Hopkin, who makes such instruments, and also play a number of online games. Finally, the “Online Activities” area lets users watch and listen to a number of fun and interactive features, such as a listening memory game.