Now how did they do that?

Could someone tell me the following: In the Founding of Durotar and the other parts of the campaign, they made the game to jump from a map to another map. For example going to the Goblin mines in the engineer Gazlowees quest to clear the mine from the kobolds. I'd like to know how did they do the mapchange thing.

By saving information about the heroes and quests to game cache and designing every map in the "enviroment" to first read the info in the game cache and then create the right units/quests accordingly. (that's why only heroes can journey between maps, they didn't implement a complex system that would allow for just any units to go through.)

Heres a mid-advanced tutorial on using game caching effectively.

Hope it helps.

Thanks for both. This will get you some reputation.