You have parked facing uphill. If you drive an automatic, you should leave your car in Park. If you drive a manual (stick shift), you should leave your car in

Set your transmission to oppose the direction in which your vehicle may roll if its brakes fail. A vehicle facing uphill may roll backward. Therefore, when you park your vehicle facing uphill, you should shift into Park (for an automatic transmission) or first gear (for maximum forward torque with a manual transmission). [Parking, Everyday Driving Skills, Chapter 3: Learning to Drive, Pennsylvania Driver's Manual]