Barsoom, the name used for Mars by its inhabitants, is a world of ruined cities, cultivated tracts, and scattered communities whose survival depends on an artificial atmosphere. The planet is at once an immense landscape crossed by travelers and a fragile, engineered habitat: beneath its ancient grandeur, life rests on machinery capable of failing.

A World of Ruins, Canals, and Cultivated Land

During the journey to Thark, the caravan crosses two sea bottoms and passes through or around ruined cities, most smaller than Korad. It also crosses the planet’s famous waterways, called canals by earthly astronomers. The cultivated districts are walled and divided by broad highways; fields, low buildings, methodically arranged trees, and enclosed animals give them the appearance of farms. Beyond them lie arid lands and desert, making each crossing a carefully timed passage between inhabited territory and open waste.

The travelers approach these cultivated regions cautiously. A warrior with a powerful field glass scouts ahead for large bodies of Red Martian troops. If the way seems clear, the caravan waits for darkness, finds one of the highways, and crosses as silently as possible. One crossing takes five hours without a halt; another consumes the entire night, and the caravan is only just leaving the high-walled fields at sunrise. The procedure presents Barsoom not as an empty wilderness but as a worked landscape in which travel brings the risk of being seen.

Cities and Political Territory

Thirty days after John Carter arrives on Barsoom, the expedition reaches the ancient city of Thark. The green inhabitants have taken their name from the long-forgotten people who built it. Thark’s hordes number about thirty thousand and are divided into twenty-five communities. Each has its own jed and lesser chieftains, while Tal Hajus rules them all as Jeddak of Thark. Five communities are headquartered in the city; the others occupy deserted ancient cities scattered across the district claimed by Tal Hajus.

The caravan enters Thark’s central plaza in the early afternoon. Its return draws no general celebration: individuals offer formal greetings to warriors or women they know, but the arrival of two captives—John Carter and Dejah Thoris—soon makes them the focus of curious groups. The city’s architecture is grander and richer still than Korad’s, yet the inhabitants value buildings chiefly for their size and vast chambers. That mismatch between monumental ruins and their utilitarian occupants makes the past visible as architecture while showing how little its original purpose governs present life.

The Machinery That Sustains Life

Barsoom’s atmosphere is artificially produced in a building containing the machinery on which life across the planet depends. The process centers on the ninth ray, separated from the sun’s other rays by finely adjusted instruments on the building’s roof. Three-quarters of the structure is given over to reservoirs that store the ray. Refined electric vibrations are then incorporated in measured proportions, and the resulting product is pumped to the planet’s five principal air centers; contact with the ether of space transforms it into atmosphere.

The system’s reserve is said to be sufficient to maintain the existing atmosphere for a thousand years. Its vulnerability is therefore not an immediate shortage of stored material but the possibility of mechanical failure: the keeper who explains the process identifies an accident to the pumping apparatus as the chief danger. The colossal building is both a technical marvel and a single point of peril, turning the invisible air that surrounds the planet into a matter of infrastructure and maintenance.

Planetary Crisis and Significance

The risk becomes a planetary emergency when the governments of Barsoom learn that the keeper of the atmosphere plant has failed to send a wireless report for two days. Repeated calls from a score of capitals go unanswered. After a thousand cruisers search for him, one returns with the assistant keeper’s mutilated body, found in the pits beneath his house. The instruments show air pressure rapidly decreasing across Barsoom: the engine has stopped.

The crisis exposes the condition on which every local landscape, city, and political community rests. The plant’s walls are so formidable that penetrating them would take months, and work has already begun; nevertheless, fortification cannot compensate for a stopped engine. Barsoom’s ancient ruins and cultivated tracts are not merely scenery for adventure. They belong to a planet whose continuing habitability depends on a complex shared system, so a failure in one building threatens life everywhere.