It is always heartwarming to come upon the monument to a child. (see below)

The Great Pyramids of Egypt, standing for more than 4000 years are the oldest known funerary monuments.

Burial Tombs and Crypts have been found dating to the time of Christ and before.

The oldest known intact  headstone type  monument  is the Chuusonji Gorintou, dated 1169 in Iwate Prefecture, Japan.

The Grave Marker below, located in Austin, Texas memorializes someone born more than 200 years ago.