Humans can recognize the fragments of a cranium in the earth, even when other bones look like shards of stone. The human brain has a specific region for recognizing faces, and is so attuned to finding them that it can see faces in a few dots and lines or punctuation marks; the human eyes cannot avoid recognizing a human skull as having once been human. 

Moreover, a human skull with its large eye sockets displays a degree of neatness, which humans often find visually appealing yet a skull is also obviously dead. As such, human skulls have a greater visual appeal than the other bones of the human skeleton, and can fascinate even as they repel. The skull that is often engraved or carved on the head of early New England tombstones might be merely a symbol of mortality, but the skull is also often backed by an angelic pair of wings, lofting mortality beyond its own death.

Hamlet, where the title character recognizes the skull of an old friend: "Alas, poor Yorick! I knew him, Horatio; a fellow of infinite jest. . ." Hamlet is inspired to utter a bitter soliloquy of despair and rough ironic humor.

When a skull is worn as a trophy on the belt of the Lombard king Alboin, it is a constant grim triumph over his old enemy, and he drinks from it. Thus a skull is a warning when it decorates the palisade of a city, or deteriorates on a pike at a Traitor's Gate. The Skull Tower, with the embedded skulls of Serbian rebels, was built in 1809 on the highway near Niš, Serbia, as a stark political warning from the Ottoman government. In this case the skulls are the statement.

The Serpent crawling through the eyes of a skull is a familiar image that survives in contemporary Goth subculture. The serpent is a chthonic god of knowledge and of immortality, because he sloughs off his skin. The serpent guards the Tree in the Greek Garden of the Hesperides and, not that much earlier, a Tree in the Garden of Eden. The serpent in the skull is always making its way through the socket that was the eye: knowledge persists beyond death, the emblem says, and the serpent has the secret. 

An old Yoruba folktale [5] tells of a man who encountered a skull mounted on a post by the wayside. To his astonishment, the skull spoke. The man asked the skull why it was mounted there. The skull said that it was mounted there for talking. The man then went to the king, and told the king of the marvel he had found, a talking skull. The king and the man returned to the place where the skull was mounted; the skull remained silent. The king then commanded that the man be beheaded, and ordered that his head be mounted in place of the skull.

The Totenkopf and skulls and crossbones have also their own meaning in relation to Death.