Day 4: Favorite Game World
Mine is a tie. My first and nearest to my heart was "The Known World" later called Mystara. But I quickly adopted Greyhawk. So when I ran games it was Mystara, but playing it was Greyhawk. Around 1986 or so my then DM and I decided to merge our worlds. We called "Oerth 3", not very original I know.
Many years later I discovered this map by Chatdemon based on an idea by James Mishler. It was exactly what I was trying to do. Plus this map was so much better than mine.
So my favorite game world of all time is Mystoerth!