Looking to do something of a large scale world. Similar to an RPG or GTA. Curious what the engine can handle as far as map size.
Not sure if this was the right section but I thank you for your response anyway.
Theoretically you can create nearly infinite worlds -> world composition tool: https://docs.unrealengine/latest/INT/Engine/LevelStreaming/WorldBrowser/index.html
But it always depends on the performance -> so the type of game, which meshes you want to use,… 
e.g the open world kite demo from epic games is around 256 km2 big v=0zjPiGVSnfI
Thank you very much man. That really helped. 