Grandpa: "You young'ins have it easy. When I was your age, I had to walk to school and home again uphill both ways!"
Grandson: Grandpa, that's imposs--
Grandpa: Don't interrupt me child! I'm telling the truth, I walked uphill both ways!
Grandpa isn't lying. How can this be (note: this is a lateral thinking puzzle with many possible solutions--most creative wins)?