Down the Hole!

Strategy
Down the Hole! is an iPad achievement. Simply go to the Achievements menu, and scroll down. (It's a pretty far way down from the Achievements page). You should see Zombie China. That's all you have to do. (This is the easiest achievement to obtain). You can get this achievement even before you start Adventure mode. It is based on the myth, that, if you dig a hole deep enough, you'll see China.

Trivia

 * The Chinese letter in the icon of the achievement means "love".
 * Going down that hole you can also see lots of other refrences to PopCap games, including Bejewled and Bookworm.