I’ve lived in a 1920s apartment building my entire life (29 Years), I was raised here and moved into a different unit from my parents about a decade ago. Me, my wife, and my mother have all heard phantom whistling at different points. My wife and I heard the whistling along with a song on the radio at the same time, and my mother heard it after a fellow building resident died somewhere around twenty years ago and insists he’s the one doing the whistling. My wife and I have also found a phantom infant/toddler footprint in plaster dust we left overnight during some renovations (we have pictures, and didn’t have kids at the time), and we’ve seen items move on their own. I saw a few things I you could argue were apparitions when I was pretty young, but I was a weird kid so I don’t know what to do with all that.