Songlines of the Navigators (Lanthanide Horizon)

The sea of Machine Space is dotted with land-islands - humming devices and precarious factories attached to the wall of that great void. The Navigators who sail the black sea use songlines, memorized map-fables, as guides.

Some songlines are common, known by Navigators of all septs.

• The Island of Shrouds, a heatstroke jungle of clear plastic sheeting.
• The Island of the Rivals, where two groups of Firstborn are locked in an endless blood feud. 
• The Island of the Great House, where a few hundred grain farmers live around a tungsten tetrahedron miles wide. They have seen Navigators before, and the people of the Great House scrape up gifts to become passengers on sept-vessels and explore the world. 
• The Island of Clouds, where some mystery fills the air with red mist that corrodes spacesuits - though this does make it a surpassing source of propellant. 

The route to the Spire is also held in common. 

Kiyonori Kikutake's 1970 Expo Tower

Others are rarer, spread across the assemblies but are known mainly by geoglyph painters and historians.

• The Island of the Lotus-Eaters, a winding building whose people dance forever pinned by dangling wires. Their home has been ransacked by Navigators - the lotus-eaters dream only of returning to its embrace.
• The Island of the Captives, whose arcology broke open from the grinding weight of time. Now machines stalk the shores of their false ocean to keep them inside until repairs can be completed.  
• The Island of the Loom, covered by the strings of its vicious guardian's web.
• The Island of the Welder, largely inaccessible without passing through a lethal conduit.
• The Island of Shining Sand, where each grain is perfectly square, glows like a diamond, and is engraved with microscopic shapes.

The routes to the Vault, the Ghostfields, and the Hanging Gardens are also rare. 

Another three are held by the assemblies - one of the last acts of the Imperious before their retirement at the end of the year is to decide which septs are allowed to forage from these more lucrative sites, which provide either multiple trade goods at once or allow more efficient foraging.

Assembly Elegiast:

• The Island of All Colors, where Firstborn tend to iridescent microbes that refine organics into hundreds of specialist chemicals.  

Assembly Cloudspinner:

• The Island of the Monolith, which has been slowly building the same 30-story-high object for as long as the Navigators have known it. 

Assembly Sidereal:

• The Island Paired, where lightning strikes and great cuboid machine-worms crawl from one island-pillar to the other. 

Another eight are fabled - known to exist, somewhere, though the route is lost.

• The Island of the Photosynthetes, whose people cracked their spherical arcology open from within, and now stand proud as kings. It is said they make fine hosts to Navigators - though with little food, as they no longer eat.
• The Island of Secrets, which is invisible to the eye and hides when sept-vessels pass by. 
• The Island of Variegated Limbs, which shift like kelp in ocean currents.  
• The Island of the Fortress, protected by a ceramic shell of surpassing strength.
• The Island of the Broadcasts, which sings a song that metal hears.
• The Island of Itself, which slowly grows across the walls of Machine Space like mold.
• The Island of the Moon, a still-sealed arcology of transparent plastic tunnels under an orbiting white light.
• The Island of the Harbor - Machine Space is haunted by the angular Dreadnought. Antenna-studded splinterer of shields, breaker of axes, scarred by its thousand victories. Surely it comes from somewhere, and returns there for repair and ammunition.