A few weather satellites transmit live images of earth as they pass overhead on 137MHz, a bit above FM radio and aircraft comms. with an antenna shaped live a V and a cheap (£30) USB radio (this one is an RTL-SDR blog v3) you can receive and decode these transmissions into images of the earth. This is an image from a Russian satellite that was launched a couple months back called METEOR-M 2-3
There's so much more you can do with SDRs. Just search for "things to do with SDR".
First of all, RTL-SDR is originally just a DVB-T TV dongle, but someone found it can send raw I/Q data in debug mode. Thus first inexpensive SDR entered the world. 24MHz-1,766MHz (in case of R820T2 tuner) for just around 5$.
Check this about page: https://www.rtl-sdr.com/about-rtl-sdr/
It also lists some things you can do with SDR.
However, make sure to pay attention to signal bandwidth. RTL-SDR can only go up to 2.4MHz in bandwidth (stably). That is however fine most of the time.
Want to try listening with SDR right now (for free)? Yes, you can: http://websdr.org/ . Select some SDR based on location/frequency range and try listening to what's there.
One note, Chrome browser introduced some bug with audio a long time ago. That's why you'll see the "Start audio" button on some pages. If you don't see it and you can't hear anything, try Firefox if you aren't using it already.