Now I'm no stamp collector* but I do think postage marks, stamps, envelopes are ace. Here are two Russian envelopes with fabulous illustrations, a beautifully simple letterpressed airmail envelope from the US and a Czech sample with great stamps.
* Said with no disrespect to stamp collectors. Although a traditionally nerdy past time, I'm a strong believer in the idea that one man's nerdy interest is another man's passion. In fact, this site is testament to that idea.
Comments