A letter sent on December 20 marked priority mail was not received until January 3rd. The recipient of the letter calculated that a snail could have traveled faster than the mail. In Poland the mail system really does earn the name “snail mail.” Here are the calculations:

Michal Szybalski calculated that it took 294 hours for the letter to arrive at his home. He also said the distance between his home and the sender was 11.1 kilometers.
Given the distance and the time, the speed of the letter was 0.03775 kilometers per hour. Szybalski calculated that a garden snail travels at around 0.048 kilometers per hour.