Vandalism

Vandalism (capitalized) is the spirit or conduct of the Vandals; thus, ferocious cruelty; hostility to the arts and literature, or willful destruction or defacement of their monuments.

More recent cases of Vandalism include the Taliban destruction of Buddhist statuary in Afghanistan.

Uncapitalized, vandalism is willful wanton and malicious destruction of the property of others.

The term is usually generalized to include undesired, non-destructive unauthorized modification (e.g. defacement?) of property.