Born Maria Elisabeth Sieber in 1924 Berlin, she was the only child to result from the marriage between assistant director and producer Rudolf Sieber and Marlene Dietrich (they were legally married until his death in 1976, despite her numerous infidelities).
At age 5, Dietrich took Riva to live in Los Angeles and she spent most of her childhood at Paramount Studios, as Marlene always wanted to keep her close and did not let her go to school (she was educated by governesses). As she grew up,…

