Your smartphone is an amazing piece of technology, but it would be nothing without a cellular network which gives you the ability to text, talk, and browse the web. You may not see most of the massive infrastructure used by your cellphone provider, but it’s there. What If You Could See Your Cellular Network?
What the World Would Look Like If You Could See Cell Phone Signals and What If You Could See Your Cellular Network? articles have amazing visualizations of cell phone network signals. There are thousands of invisible signals bouncing around us all the time, and the world would be a very different place if we could see them. Data visualization artist Nickolay Lamm created psychedelic images of the cellphone signals that live in the air, but are invisible to us. I really recommend you to take a look at them and be amazed.
There are also many other radio signals than cell phone network. Check also What If You Could See WiFi? and What the World Would Look Like If You Could Actually See Wi-Fi Signals.