Masks have been used throughout history and across cultures as a means of concealing one's identity, but also as a way to express or assume a different identity. Here are some examples:

1. Anonymity: Masks can be used to hide one's face and protect one's identity, making it possible to remain anonymous in public.
2. Disguise: Masks have been used as a disguise in various contexts, such as in theater, costume parties, or even criminal activities.
3. Superheroes: Superheroes like Batman and Spider-Man wear masks to conceal their secret identities.