For the Pulitzer Prize-winning playwright and librettist Nilo Cruz, Frida Kahlo and Diego Rivera are no mere historical figures. The giants of Latin American art, twice married, are larger than life, their legacies transcending time and place. So when Cruz started writing an opera based on their life together, he set out to do more than trace the highs and lows of their relationship. “Their relationship was turbulent, contradictory, passionate, destructive, nurturing,” Cruz says.