500 error on one page in entire site only showing error "You are here" instead of administration content
If you have shell access to your server, you could check the actual php error logs on the server- which should indicate the exact culprit.

If you recently updated Drupal core or some contrib modules, you may want to make sure the update process completed successfully.  

Also, if you were editing/adding a custom feature module, content types, field collections, paragraph bundles, or other entities referenced by the specific "People" content type, you may have accidentally removed a required field that could cause the page to break- in which case, restoring a backup database could fix the issue.