Grand Teton National Park is a great park not far from Yellowstone with similar wildlife, but without the geothermical experience.
Mount Rushmore National Memorial is centered on a colossal sculpture carved into the granite face of Mount Rushmore in the Black Hills, South Dakota. The sculpture features the heads of Presidents George Washington, Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln.
The Yellowstone is the oldest National Park in the USA and hosts a wide variety of animal life (incl. bears and buffalo) and vegetation. The natural beauty will make quite an impression. Beneath the Yellowstone there is volcanic activity that causes many hot pools and geysers ("Old Faithful").
Charleston (South Carolina) has a long history that is reflected in the colonial buildings. Long it has been one of the major cities in the USA. Nowadays it is a real pleasant city.
Chicago, on Lake Michigan, with nick name The Windy City, is one of the largest US cities. The Sears Tower is one of the tallest buildings in the USA.
Death Valley is one of the driest and hottest places on planet earth. It is also the lowest point in North America. Less known: you can also find the "Devil's Golf Course" here, where you for sure lose your golf balls.
Everglades National Park is a large network of wetlands and forests in Southern Florida with animal life like panther, crocodile and manatee. The park is the largest tropical wilderness in the United States and a World Heritage Site.
Los Angeles (aka. City of Angels) is the 2nd largest city in the USA and has a lot to offer, including great shopping (a la Pretty Woman), Hollywood, Venice Beach and sports (L.A. Lakers).