Youn late February, four days after Russia invaded Ukraine, Inna Vdovichenko, a staffer in the Odessa office of the Jewish humanitarian organization JDC, was sitting in Natalia Berezhnaya’s home when an air raid alert began. Sirens blared. For Vdovichenko, who had come over to keep Berezhnaya company and to see if she needed food or medications, it was the second time she’d heard such sirens; the noise brought with it a wave of fear. But for Berezhnaya, 88, a Holocaust survivor, there was also a feeling of déjà vu. “She said, ‘I was a little girl when I had to...