But Rob Napier says he left something a lot more valuable on a train.
The retired shipping consultant tells the AP he forgot a rare 17th-century violin on a train west of London on January 29th.
He says his first reaction was to try to jump on top of the train, but realized that would stupid.
The violin has been in his family for more than 60 years.
It's worth about $390,000 and a $20,000 reward is now being offered for the violin's return.
