The last period began in 1966. From that year until the year of his death, Obregón's painting insisted on an effusive and romantic style and on obsessive themes. As Juan Gustavo Cobo wrote: "His motifs haunt him, they fade away, reappear, merge." Working in series, Obregón painted Anunciaciones (Annunciations), Floras, Ángelas, Violadas (Raped), Zozobras (Perils), Memorias de Grecia (Memoreis of Greece), Magos de la Popa (Magicians of La Popa), Blas de Lezos, Cosas de la luna (Moon Things), Bachués, Leyendas de Guatavita (Legends of Guatavita), Paisajes de Cartagena (Cartagena Landscapes), Amazonias, Copas y océanos (Crowns and Oceans), and Vientos (Winds), an incomplete list. Although he did not accept it ("I think oil is completely obsolete. Acrylic is the medium of the twentieth century."), Obregón was not able to infuse his later works with the mystery and strength of his oil paintings before 1966, the year he started working with acrylic.