I'm charmed by the story of Owney, the mascot of the postal system in the 19th century. As the story goes, Owney was a mutt who found a home of sorts in the post office in Albany, New York, in 1888. He soon began to travel with mail bags on mail wagons and trains, making his way across the state and even to Asia and Europe.
Mail clerks on the trains considered Owney a good luck charm because no train Owney rode was ever in a crash. The clerks marked has travels by placing medals on his collar, one for each stop. Eventually, the tags got too heavy, so Owney got his own harness for all of the tags, which jingled when he walked. When Owney died in 1897, mail clerks raised money to have his body preserved (which I find a little less charming!), and he's been on display at the Smithsonian ever since.
Owney is now featured on a Forever stamp, which is scheduled to be released today. I think the stamp is so sweet, I might just send myself a letter!