Here are some examples:
* Appearance: "After the accident, the car was unrecognizable." (It was so damaged that you couldn't tell what kind of car it was.)
* Sound: "The singer's voice was unrecognizable after the surgery." (It sounded completely different.)
* Situation: "The city was unrecognizable after the earthquake." (The buildings and streets were so destroyed that it looked like a different place.)
Synonyms for unrecognizable include:
* Unidentifiable
* Indistinguishable
* Unfamiliar
* Transformed