This is the only episode in which the final four were all male competitors.

This is also the only episode of Friends to take place in "real time".

This was the only episode of the show ever filmed.

It is also the only episode of the three in which you can see the ending coming a mile away.

Also, this is the only episode to feature something seen or mentioned before.

Therefore, this is the only episode and special to win $1,000,000 in show history.

This is the only episode of the series that does not focus on the criminals.

This the only episode in the entire series where the main story is based on a past event.

It is the only episode in the series that was rated.

From here it can be concluded that this was not the only episode produced.