You have parked facing up a steep hill. If you drive an automatic, you should leave your car in "park." Which gear should you use with a manual?

It is best to leave your car in "park" if you are driving an automatic. If you are driving a manual, you should choose a gear that will oppose the direction your car might roll. In this situation, you should leave your car in first gear. [Parking on a Hill, Parking, Laws and Rules of the Road, California Driver Handbook]