The sundial has been a way to measure time since the Egyptians developed them over 3,500 years ago. Historians even believe that the obelisks of ancient Egypt were used to measure time even earlier.
The sundial monument in the Cave Hill Cemetery at Louisville, Kentucky, not only measures time, but also marks the graves of the Rae family. The Rae Family sundial surrounded by a marble colonnade punctuates that point with the symbol of the winged hourglass—a symbol that denotes how quickly life passes by, how fleeting time is.
The sundial marks the passage of time and in funerary art symbolizes the passage of time. The sundial and the winged hourglass are both metaphors.