Editing The Culture (section)

===Shellworlds===
Shellworlds are introduced in ''Matter'', and consist of multilayered levels of concentric spheres in four dimensions held up by countless titanic interior towers. Their extra dimensional characteristics render some products of Culture technology too dangerous to use and yet others ineffective, notably access to hyperspace. About 4000 were built millions of years ago as vast machines intended to cast a forcefield around the whole of the galaxy for unknown purposes; less than half of those remain at the time of ''Matter'', many having been destroyed by a departed species known as the Iln. The species that developed this technology, known as the Veil or the Involucra, are now lost, and many of the remaining shellworlds have become inhabited, often by many different species throughout their varying levels. Many still hold deadly secret defence mechanisms, often leading to great danger for their new inhabitants, giving them one of their other nicknames: Slaughter Worlds.