Mt. Rushmore.
Port Arthur convict settlement.
Mount Rushmore National Monument is the name of the landmark which has the carvings of the faces of four US Presidents. Mount Rushmore is located in the Black Hills of South Dakota near Keystone, SD.
Manmade places are usually named for famous people or for landmarks, like John F. Kennedy airport or Dulles International airport. Pick either a famous person or a good local landmark and name your airport after one of those.
Lake Powell
Lake Sunaper, nh
The Aloha Clock Tower for something manmade and Diamond Head made by nature.
The Grand Canyon.
It is the Lincoln memorial
US/statue of Liberty
The name of the bridge that is a landmark in San Francisco and California is the Golden Gate Bridge
If by tn you mean Tennessee, then the landmark would be Graceland, the mansion of US singer Elvis Presley.
Manmade actually.