Now, 34 years later, that same subway piece is slated to be sold at the Spanish auction house Duran Subastas.

Haring's work up for auction at Duran captures the conceptions behind some of the most prominent artists of the 1980s. Consumption of contemporary art increased so sharply that prices reached absurd levels. More and more artists began to practice their craft in public spaces. The avant-garde art scene from the late 1970s to the 1980's consisted of a new-expressionist style with more figurative motifs in vivid colors, which focused on such raw human concepts as anxiety, excitement, exclusion and ambiguity.

Keith Haring (1958-1990) began his career in the subways of New York, but unlike other street artists who used a more permanent spray paint, Haring chose to use crayons and chalks which were easily wiped away. Haring was part of the New Expression era, his art was deeply personal and characterised by its open vulnerability which explored such once-taboo subject as AIDS and New York's crack epidemic.

In commercial terms, Haring's art was very successful, his motifs lent themselves easily to being printed on t-shirts, buttons and stickers, all of which made for perfect marketing for his activist campaigns. Although Keith Haring passed away prematurely at the age of 32, his art lives on thanks to the time he invested in creating public murals.

Keith Harring's work Octopus Alien with UFO will be up for auction at Duran Subastas on September 21. Check out the full catalog here.