A block from where I grew up is a huge sinkhole, formally Seven Oaks Oval Park, and informally "the oval" or "the hole." I have fond memories of playing here as a child.
This picture doesn't do justice as to how deep it really is. I might have to try harder to show its depth another day.
It was already platted on this 1903 map. (Plate 47 shows the park.) According to one article I read, it officially became a park in 1922, but I haven't been able to verify that.
