Small!

I conduct a sort of postal experiment: I sent to Bryon (the USA) a very small card Oz-themed. (Sorry, I did not take any picture of it!)

It arrived safe and sound, and the reply came as a similar card, slightly smaller than the postal regulations allow. It travelled 28 days before reaching my mailbox. 

It was delivered while it was really pouring outside, hence those strange marks and the illegible postmark. But it was perfectly readable inside, and the Judy Garland's stamps remained in good condition.