Where the Buggalo Roam - S4-E6
Corrected entry: When everyone goes to Mars to visit Amy's parents (and celebrate Mars Day) it is shown that Mars is, like today, a red, desolate wasteland of dirt. However, in the episode "Mars University", Mars is shown to be filled with jungles and plant life. Maybe that is the hemisphere that the Wong family doesn't own, but if that were true, then why would Inez (Amy's mom) say they had the best hemisphere when the other one is, theoretically, filled with grasslands and jungles et cetera?
Correction: They own that hemisphere, therefore, they're obviously going to think it's the best.
Xofer