Does Guild Wars have instances like World of Warcraft?

Question

Does guild wars have instances like WoW where you group with other people and down bosses etc etc?

Answer 1

Yes, it does.

When you walk outside of a town or an outpost, or a mission, you are in your own world map.

When you enter a mission alone, or with a group of friends, you again are in your own world, for you and your party.  

Answer 2

All areas outside of towns is done through instances.

Answer 3

Yes, yes it does.