living proof
living proof [phrase]: [usually 'verb-link phrase', often 'phrase that'_, 'phrase of noun']
If you say that someone is living proof of something, you mean that their actions or personal qualities show that a particular fact is true or that a particular quality exists.
- He is living proof that some players just get better with age.
[Collins Cobuild Advanced Learner's Dictionary]
living proof
If someone is living proof of a particular fact, they are a good example of how true it is....
- I will remember them as living proof that you can have too much of a good thing.
[Longman Dictionary of Contemporary English]
Though usually applied to persons (He / she / you ... is / are living proof ...), the usage is broadened to human institutions:
- The stock exchange is living proof of that fact.
[Cambridge Dictionary; Hansard]
- It is living proof that public services can be both efficient and popular.