When I was much younger and in the Boy Scouts, I took an Introduction to Amateur Radio class at a local church. I was actually really into it for a while, and saw myself one day having expensive radio equipment, and contacting people on all corners of the globe; meeting new people, learning about other cultures, playing pranks on people over the radio, and of course what was obviously the most appealing aspect of all, collecting QSL cards.
A QSL card is a postcard sent out after two stations make contact with one another. It is essentially the station's calling card. I loved the idea of collecting hundreds of individually designed cards from all over the world, and making my own to send out. But for whatever reason, after the class was over and I got my merit badge, I never followed up and got my radio license. Probably had something to do with the giant book you had to study for the test you had to take in order to get approved for the license. Plus during this time people were just starting to get the internet, which although lacking a printed element, far surpassed amateur radio in opportunities to talk to people from other countries, meet new people, or learn about other cultures. Not to mention all the other useless stuff people actually use the internet for.
However, sometime before the excitement faded, my Uncle Bud got word of my newfound interest, and gave me his collection of QSL card from the late 50s and early 60s, when he would have been the same age I was, probably taking a ham radio class for Boy Scouts at a local church. Only during that time there was a lot less to distract a kid from following through and getting their ham radio license, and thus collecting QSL cards for a few years - before moving on to other endeavors. These are the best cards from Uncle Bud's collection. Most of the designs took advantage of modernist elements that also stand for radio iconography, such as abstracted power lines and radio towers, grid-like lines, and geometric shapes - mainly circles. Interesting to note that Switzerland has the warmest, most playful, and illustrative design.