There is something oddly fascinating about radio waves, radio communications, and the sheer amount of innovations they've enabled since the end of the 19th century.
What I find even more fascinating is that it is now very easy for anyone to get hands-on experience with radio technologies such as LPWAN (Low-Power Wide Area Network, a technology that allows connecting pieces of equipment over a low-power, long-range, secure radio network) in the context of building connected products.