Differentiating results of SELECT query

I am working with two tables, "rides" and "locations" both shown below.  The 'start' and 'end' fields in table "rides" relate to the 'location_key' in table "locations."

I need to design a query where I can differentiate the start address from the end address. I am looking for a way to produce the same result that these two queries produce, but in a single query. If only Union functioned a little differently...

SELECT address AS start_address, ride_key FROM rides, locations
WHERE ride_key = '8'
AND START = location_key

SELECT address AS end_address, ride_key
FROM rides, locations
WHERE ride_key = '8'
AND END = location_key

Table: rides
+-------------+---------+-------+
| ride_key | start | end |

+-------------+---------+-------+
| 8 | 15 | 16 |

+-------------+---------+-------+

Table: locations

+-------------------+-----------------------------+


| location_key  | address                  |

+-------------------+-----------------------------+


| 15                 | 1234 Wilsher Blvd.  |

| 16                 | 999 Sunset Blvd      |

+-------------------+-----------------------------+