21. Bohemian Grove, United States

Unless you are part of the club, you can't get in. The restricted 2,700-acre campground in Monte-Rio, California, is home to an exclusive gentleman's club known as the Bohemian Club. Each July, Bohemian Grove hosts some of the world's most prominent men for a two-week retreat. 

Members of the Bohemian Club include presidents, government officials, musicians, artists, and business leaders. Whatever happens here is top-secret, and the only rule is that you can't talk about business. Most people wouldn't want to be apart of this club anyway.