Victor Lustig sold the Eiffel Tower to a scrap metal dealer, twice.
Here's a set of instructions known as the "Ten Commandments for Con Men" attributed to Lustig:
- Be a patient listener (it is this, not fast talking, that gets a con man his coups).
- Never look bored.
- Wait for the other person to reveal any political opinions, then agree with them.
- Let the other person reveal religious views, then have the same ones.
- Hint at sex talk, but don't follow it up unless the other person shows a strong interest.
- Never discuss illness, unless some special concern is shown.
- Never pry into a person's personal circumstances (they'll tell you all eventually).
- Never boast - just let your importance be quietly obvious.
- Never be untidy.
- Never get drunk.
These techniques are remarkably similar to those I've employed over the years as a writer, with the exception of "never get drunk."