Lego Space Space subtheme in which the entire theme is "good", "bad", or "civilian". Life on Mars is a space theme released in 2001, around a time of increased curiosity about the red planet. The theme revolved around the concept of the lifeforms that could possibly exist on Mars. This was the first Space theme to feature two types of minifigures: human astronauts and Martian aliens. The sets denote peaceful coexistence between the two species on the planet Mars. The "Life on Mars" theme pioneered several unique aspects in Lego in general. It was the first Lego theme to utilize a pneumatic
A Princess of Mars the planetary romance had become very popular in the emerging science fiction pulp magazines. The novel can also be classified as the closely related genre sword and planet, which consists of what are essentially sword and sorcery stories that take place on another planet. "A Princess of Mars" is widely considered to be the archetypal novel of the sword and planet genre. The novel also shares a number of elements of Westerns, such as desert settings, women taken captive, and a climactic life-or-death confrontation with the antagonist. Burroughs employs a literary device for "A Princess of Mars" to which he