Who created the missions? (and why?)

The answer to this question is more than just a simple sentence. The missions were created by many different people: a few with the idea, a few who started the expeditions, a few who acutally built them, etc. To find out exactly what you want to know about the creation of the missions, click on the button that has the title that best matches what you are looking for.

Whose idea was this anyway?
Why missions? (and why not a hotel chain?)
Who actually built the missions?
Where did they put them?