Which landmark have you visited?

In one of travel trade magazines that I read, they mentenioned a survey conducted by Greyhound. As summertime is almost officially here, it's time to hit the road. For many people, that means exploring our country. The survey discovered that 82% of the people take at least one leisure trip a year, but few include our nation's landmarks. Below are the most visited landmarks of the people surveyed...
42% Washington Monument
39% Empire State Building
38% Golden Gate Bridge
36% Grand Canyon
35% Niagra Falls
28% Hoover Dam
27% Liberty Bell
19% Mount Rushmore
25% None of these

Which national treasures have you visited? What did you like and why should someone go there? Share your thoughts with us on this blog.