Low Beams and Highbeams both went out

Hello, I was driving home from work tonight and noticed my headlights were both out on my '72 Valiant. I wiggled the headlight knob some but it had no effect. I then pushed down on the high beam switch on the floor board. The high beams came on for a split second and then burned out.

Does anyone have any suggestions as to what the cause could be? I've never had both lights go out at once. And I had just replaced one of the bulbs barely a year ago.