I'm flying the old route, but the ground has changed

I'm in the cockpit, low over a city I know by heart — only the rooftops are wrong. Streets line up where they should, but the landmarks I'd swear by are gone, replaced by things I don't recognize. I keep checking the map on my kneeboard and it's blank, just yellowed paper. Not scary, exactly. More like coming home to find someone repainted every door.