Calavera is a representation of a human skull. The term is most often applied to edible or decorative skulls used in the Mexican celebration of the Day of the Dead and the Roman Catholic holiday All Souls' Day. Skulls usually represent a departed soul.

Marigolds, or flowers in general, represent the fragility of life. The marigold most commonly used in Dia de los Muertos celebrations is the Targetes erecta, Mexican marigold or Aztec marigold, otherwise known as cempasuchitl or flower of the dead.

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From the gallery https://pbase.com/britestar/day_of_the_dead_2019