Pokemon GO: What you'll find in each kind of Pokemon Egg
In your Pokemon Go adventures, one thing you're bound to realize is that Pokemon Eggs are the real deal. Not only do they encourage you to get out and walk around -- after all, you can drive to a PokeStop, but you pretty much need to hoof it to hatch those Eggs -- they provide an alternate method to catching Pokemon on a slow day.
If you've found enough of them, you've also undoubtedly realized that the Pokemon Egg comes in three varieties, distinguished by the distance you need to walk to incubate each one. Some Eggs require just a 2 km jaunt, while others need you to walk 5 or even 10 km to see what's inside.