Mind Voyager Achievement in Bastion

The Who Knows Where trips are basically horde arenas, accessed through the items at the bottom of the Bastion. By clicking on the Smoking Pipe, Bed Roll, Cooking Pot, and History Books you will be transported to these arenas. You need to do each of these eventually with all ten idols unlocked in the Shrine for other achievements, so I'd suggest not bothering with them on your first playthrough. See "About the Author" for more information.

Note: The Who Knows Where location visited from the History Books is not required for this achievement (and it is not available until your second playthrough), but it has two achievements of its own and will help toward Score Attack Mode.