There are lots of online Shortwave receivers. You could listen to radio signals from all over the world. I began shortwave listening in my teens & I still love it.
There are many hobby (pirate) stations. Numbers (spy) stations still exist. There are radio amateurs to listen to. International Maritime radio nets. Miltary stations. All sorts still there.
One of the best online recivers is at the University of Twente.
http://websdr.ewi.utwente.nl:8901/
You could also spend sometime watching aircraft.
https://www.flightradar24.com/
Or shipping
https://www.marinetraffic.com/en/ais/home/centerx:14.2/centery:52.1/zoom:6
Both of the above sites allow you to move the map & zoom in & out. So you can watch aircraft & shipping where ever you want.
Or how about listening to radio scanners in the USA or anywhere else? Following a terrorist attack in the US few years ago, I spent my evening listening to the radios of the local Police & Fire Service.