Just Cause 2: Side Missions?

[Slachtbeest]

Not finding (or missing) any info on it... but with a world that huge (and stunningly beautiful), I'm assuming there are going to be a lot of side missions to find through exploring?

I know it's not like "RPG exploring" to find missions, but all that open space would end up being a waste of space without a ton of things to actually do in all that open area.

Thanks for any info.