There are an amazing number of little airports that existed in the 1950s-1960s heyday of general aviation that are buried under houses or light industry now.
Not so ancient, but burial; lots & lots of burial.
Most lightplane airports suffered at least one fatal accident during their lifetime either on property or nearby. So there’s some house, store, or office built atop a crash site.
E.g. from yesterday…
That airport & dragstrip still exist (Duh) but how much longer before they’re under nondescript suburbia like so many of their former brethren?