During World War II Michelangelo's David was protected in a brick "beehive"

From Futility Closet:

In January 1943, a brick "hive" was built around Michelangelo's David to protect it from incendiary bombs.

Two and a half years later, preservationist Deane Keller wrote to his wife, "The bright spot yesterday was seeing Michelangelo's David at length divested of its air raid protection. It was dusty and dirty but it was a great thrill."

(From Ilaria Dagnini Brey, The Venus Fixers, 2010.)