My time has come!
The above stereographic image is for cross-eyed viewing (most stereograms are wall-eyed, so you may need to put your finger in front of your screen until this one comes into focus)
This is an image of Honolulu, Hawaii, published by NASA. Note Diamond Head (the volcanic crater) in the south.
Here are some other stereopairs published by JPL:
Wheeler Ridge, California
Mount Saint Helens
Salt Lake Valley, Utah
Wellington, New Zealand
If you have astigmatism or greatly different lens prescriptions per eye, it may be very hard for it to work.
If you do have astigmatism, you can kind of 'squeeze' or scrunch your eyelids down to compensate as you cross your eyes, and it may work better without glasses and closer up
Some people it just never works with