Some of the world's most exclusive restaurants require year-long waits, resale prices in the thousands, or even a handwritten postcard just to be considered. If you really wanted to go to a restaurant that required it, would you send a handwritten postcard?

U.S. restaurants also appear on the hardest-to-book list, including a San Francisco steakhouse with a secret menu and a New York restaurant with no menu. Have you ever been to a restaurant that had a secret or usual menu?

These are the top 8 hardest to book in the world. Have you been to any? Comment your experience below!