American Country: Bluegrass, Honky-Tonk, and Crossover Sounds

American Latin Music: Rumba Rhythms, Bossa Nova, and the Salsa Sound

American Rock: Guitar Heroes, Punks, and Metalheads

Bruno Mars: Pop Singer and Producer

Katy Perry: From Gospel Singer to Pop Star

United Kingdom

Indonesia

Italy

Iran

South Korea

Norway

The Gateway Arch

Ghana

The Erie Canal

Tools and Treasures of Ancient Greece

Tools and Treasures of Ancient Egypt

The Hoover Dam

The Golden Gate Bridge

Tools and Treasures of Ancient Rome

Hero Military Dogs