When I was at the card show today I found a booth that had some cheap Mayo and as I was going through the cards I needed, I stumbled upon this card:
I've looked at my Mayo needs list a bunch recently but I had never noticed that there was a Marconi card in this set. The moment I saw it, I knew there was a problem. I flipped it over and sure enough, it claims that Marconi invented the radio.
This story is one of those things that everyone believes but is not actually true. Marconi did not invent the radio. Nikola Tesla invented it. If you don't believe me, PBS covered this issue when they did a special on Tesla. And if PBS isn't a good enough source, check out this U.S. Supreme Court Case: Marconi Wireless Telegraph co. of America v. United States. The Supreme Court determined that Marconi's patents on the radio were invalid because Tesla's patents came first.