Canyon is human colony planet slightly bigger than Mars orbiting around an orange-yellow sun.
The planet was originally uninhabitable for Humans and Kzinti alike with the air being too thin to breathe. The planet had just sufficient atmospheric density to support photosynthesis-using plants, with lichens being the predominant lifeforms on the planet. Animals never developed.
It was annexed by the Kzinti Empire with the help of compressors and domes and named Warhead due to its proximity to the unconquered Pierin worlds. The planet was attacked by the human colony world of Wunderland during the Third Man-Kzin War with a giant version of a Slaver disintegrator combined with a similar beam that suppressed the charge on the proton, when fired the two beams would touch thirty miles apart from each other and produce a current flow. The weapon created a gash on the surface roughly 12 miles deep and the size and shape of the Baja California on Earth. Kzinti factories and housing turned to monatomic dust and the few domes protected by emergency stasis fields sunk under the lava exposed by the explosions. The planet was surrendered to humans at the end of the war.
The canyon from which the planet takes its name radically changed the planet's ecosystem as air and water concentrated in the new depth and dust from its formation covered the surface. A sea formed at the bottom of the canyon with a long, narrow island at its center where the lava welled higher before it cooled. The surface became dry and airless killing most of the native lichen while the canyon became inhabited by humans and terrestrial and kzinti lifeforms who thrived in the now comfortable air pressure and abundant water.
The walls of the canyon are now covered in buildings, with the rim wall being home to the hanging Lichen Gardens and the island at the bottom having a park running down the middle imitating the look of a Kzinti hunting park with a mixed vegetation of green Earth and orange and pink Kzinti plants.Another popular tourist attraction are the elevators running up and down the canyon walls, a relic from the time before the transfer booth was invented. The planet is as popular with Kzinti tourists as with human tourists.
People from Canyon are knowns as Canyonites and are low-gravity types with tall, thin bodies. They are pale due to the sun's orange hue.
The surface of Canyon is now only home to mines (the planet has radioactive materials) and a large lichen preserve. Although, Louis Wu observes a lichen growing out in the wild in the desolate surface after being captured by the Hindmost.