This world and the novels set in it are, in generic terms, informed by the horror, fantasy and science fiction traditions.
Cobsea lies inland and borders the Cacotopic Stain, a large wasteland created by the unreliable magical energy known as Torque.
A wealthy industrialist attempted to build a transcontinental railway that would link New Crobuzon with Cobsea and Myrshock, as the two states are trading partners, but was unsuccessful.
West of the Cymek Desert lies the Galaggi Veldt, which is home to Tesh and is neighboured by the Witchocracy, which it goes to war against New Crobuzon with in Iron Council.
The khepri are believed to be native to this continent, but were driven out by an event known as The Ravening, and now live as refugees in various cities in Rohagi, although primitive khepri are rumored to still inhabit Bered Kai Nev. Gnurr Kett is an island that lies 2,000 miles (3,200 km) south of New Crobuzon and 500 miles (800 km) east of the Cymek Desert.
This colony is the only known remnants of the Malarial Queendom, a brutal regime that was active in the areas of Bas-Lag with a warm climate.
Very few people choose to go to Nova Esperium of their own volition because of the long journey to the colony and rampant disease, but New Crobuzon's government pays for the passage of any volunteers.
The pirate city of Armada is a mobile city-state consisting of numerous ships lashed together to form a large, connected settlement.
Armada moves around the Swollen Ocean by means of a small fleet of tug ships, and is the central setting of The Scar.
People considered criminals (or of lower classes) in their former home states are recast as equals upon joining Armada, and often go on to hold positions of power.
During The Scar, the rulers of Garwater riding, the Lovers, carry out a plan to raise the legendary avanc to give Armada ultimate power over the seas.
Along with a team of scientists and engineers, and against the wishes of several of the other ridings, Garwater is able to summon the avanc using great physical and magical energy.
Seeking a milder place to live than their homeworld, which had a cycle of days and nights that created oceans of molten iron and froze the atmosphere, the Ghosthead built a "metal fish" and used it to find Bas-Lag.
The Ghosthead harnessed the energy from The Scar by a process called "possibility mining", and used this power to gain control over all of Bas-Lag.
The First Umbric Age, in which the Bas-Lag novels are set, is a period of feuding between the states on Rohagi after the Ghosthead Empire falls.
The Full Years are New Crobuzon's golden age, when the city achieves its greatest advances in science, technology, and thaumaturgy.
When heliographs of the destruction are taken by a militia research team and leaked to the New Crobuzon public a century later, widespread riots almost bring down the government in 1689.
Around the year 1679 (a century before the events of Perdido Street Station), khepri civilization in Bered Kai Nev is wiped out by a disaster described as "The Ravening".
Since many of its speakers have either sewn-shut mouths or larynxes too decayed to form sounds properly, it consists of a series of coughing grunts, with "intricately timed pauses" that are as important as the spoken element.
Cactacae bodies are fibrous, with wooden bones, making them notoriously difficult to kill or wound with normal weapons; bullets pass nigh-harmlessly through them.
Their weapons of choice are Rivebows, oversized crossbows that fire a spinning metal disc capable of shearing off Cactaceae limbs.
Garudan law is based around the principle of freedom of choice; all their crimes are forms of "choice-theft", denying another being the right to choose their own fate.
Capable of survival in salt and fresh water, as well as in the air, they can communicate telepathically with a variety of aquatic species including whales and Cray.
According to Iron Council and several minor mentions throughout Perdido Street Station, the hotchi are a race of humanoid hedgehog people who ride a domesticated breed of giant rooster.
They practice a unique form of martial, arena combat called mortu crutt, which emphasises pounding, hammer-like strikes, as edged weapons are nearly useless against them due to their rapid coagulation.
Driven to near-extinction after the railroad destroyed their indigenous swamp lands, the Stiltspear were a race of quadrupedal creatures with insect-like legs and radially symmetrical hands that can be closed into spears, with which they hunt.
Most notably, Striders seem to partially phase into and out of solid existence; said to be "dimensionally disrespectful," parts of their bodies may seem to vanish or not interact with ordinary matter in predictable ways.
Rather than imprisoning criminals, the city of New Crobuzon will send them to punishment factories, where "bio-thaumaturges" warp and twist their bodies in a variety of ways.
Another implication of dropping the colourbomb is that it was done to hide the extent of the torque weapon's devastation of city of Suroch, which later revealed to be the unnamed opponent in the Pirate Wars.
In all three novels there are also several mentions of clockwork gems, metaclockwork, sentient robot-like constructs operating with difference engines, and many other inexplicable or fantastic instances of science, magic and combination of both.