The descent into the Odesa National Fine Arts Museum’s 200-year-old grottoes is laden with both heavy allure and 100% humidity. Kateryna Kulai, the museum director, leads the way down a winding staircase from the basement of the museum – tucked inside Odesa’s opulent, neoclassical Potocki Palace – to the natural, flooded caves. The museum’s intricate history is mirrored in its physical layers. Passages from the grotto fan into catacombs that once led to the Black Sea. In World War II, they protected civilians and artworks from Nazi bombings. Since Russia’s attack on Ukraine in February 2022, the underground has once again served as a refuge. Frames stripped of art lie in piles in the museum basement, the artwork itself hastily packed and funneled to secret, safer locations. Ms. Kulai says she dreams of the day when they are restored to their former glory. Why We Wrote This Ukraine’s cultural institutions aren’t just casualties of the Russian invasion of the country.…