My Latest D&D5 Unified World Map

The idea here is to connect all the world campaign settings together for storytelling purposes so that player parties can travel from one campaign to the next within the context of the story. Eberron is harder to get to than the others because it has a bit of technology.

The story I'm promoting is that time traveling magicians from various times went back to Earth around 10,000 years ago and started to rebuild Earth in their images. They restrict guns because it directly challenges their magic and authority in ruling the D&D world.

I started with Maztica which is reported to be based on Columbia. Hollow World, Thunder, Mystara, and Savage are all supposed to be connected in these campagins so I kept them all in South America.

Hyboria, I cut off the western part of Africa because that is what one guy did when trying to match Howard's world with Earth and it turned out well.

I put Ravenloft in the Balkans, of course.

Birthright is a European like world so I put it in Europe.

Lankhmar is based on Scandanavia.

Rokugan is based on The Five Rings which is Japanese.

Kara-Tur based on a wide range of Asia.

Here is the map.
kira3696.tripod.com
     I'm kinda dubious of the whole idea and would advise limiting scene changes to magic portals or such.
    The first problem is this encourages the players to head into unexplored territory where you have no idea what should be happening.  Better that any change in bckground be planned and special.
     Tho basing the map on the real world has benefits, it also limits you.  It is not crossovers you want to make, but crossover you have to make or can't make.