jimmywilson wrote:719hz.wav is an image when viewed through a spectrogram.
You can see the earth in the center, and europe and africa on the earth.
The file is called "719 Hz". I marked 719 Hz on the spectrogram with the marker, as you can see when the frequency marker is at 719 Hz (sorry 721 Hz, that's the closest I could get) it is located over Southern Africa.
Here's the image scaled down: