Mourning is, in the simplest sense, grief over someone's death. The word is also used to describe a cultural complex of behaviours in which the bereaved participate or are expected to participate. Customs vary between cultures and evolve over time, though many core behaviors remain constant. Wearing black clothes is one practice followed in many countries, though other forms of dress are seen. Those most affected by the loss of a loved one often observe a period of grieving, marked by withdrawal from social events and quiet, respectful behavior. People may follow religious traditions for such occasions. Mourning may apply to the death of, or anniversary of the death of, an important individual like a local leader, monarch, religious figure, etc. State mourning may occur on such an occasion. In recent years some traditions have given way to less strict practices, though many customs and traditions continue to be followed.