on Earth but (in the world) on the right/on the left on the back of/on the front of (a letter, an envelope, a sheet of paper) on the beach, on the island on the west/east coast
AT
at the traffic lights, at the crossroads at work, at home, at school, at university at the entrance at the hairdresser's, at the doctor's, at the butcher's at 34 King Road, at 107 Merrion Street
IN
in the picture, in the photo in the west/east in the front of/in the back of (a car) in a book in a newspaper, in a magazine
