The Wall of Darkness

The Wall of Darkness is a short story written by Arthur C. Clarke and first published in July 1949 in the magazine "Super Science Stories". It was subsequently published as part of a short story collection in "The Other Side of the Sky" in 1958 and can presently be found in The Collected Stories of Arthur C. Clarke (2000).

This is the story of Shervane, an inquisitive young man who attempts to understand the unique structure stretching across the equator of his planet. This "wall of darkness" is set on an alternate-universe earth different from our own.

The story begins with a description of Shervane's world. Its sun, Trilorne, warms only one side of the world, causing the northern half of the planet, the Fire Lands, to be too hot to be hospitable. The southern half of the planet is much colder and is known as the Shadow Lands. In the middle is a land belt of a temperate climate where the entire known population resides.

As is custom on this world for the eldest son, Shervane makes a year-long pilgrimage to the southern cities of his ancestors in order to study with his cousins. While in the southern cities, Shervane meets Brayldon, a young man aspiring to become a great architect. Together, they explore the wall that rises in the south.

The wall is mysterious in its origin and there are many theories as to its existence: some think that the creator of the world built the wall in order to separate, the living from the dead or yet to be born; others believe that the wall was made by the First Dynasty of man. Many believe that gazing over the wall will induce madness.

After finding the immense wall insurmountable, Brayldon and Shervane return to their studies and shortly thereafter, to their former lives. Due to a storm in his home town that claims his entire family, Shervane becomes the beneficiary of an immense fortune that makes him the richest man the land has known for generations. Meanwhile, in his own lands, Brayldon achieves his dream of eclipsing his architect-father in greatness.

Though for decades Shervane and Brayldon do not see each other, they regularly keep in touch through exchanged messages. As they near middle age, Shervane decides to use his fortune and Brayldon's architectural expertise to erect a stairway to the other side of the wall. The gigantic stairway takes seven years to complete. When finished, Shervane alone will venture across the wall. Though this is in part to spare anyone else possible madness, there are other unmentioned reasons as well.

Shervane climbs the final twenty feet of the wall by means of a simple hoist and walks across the wall. As he looks out across the wall, he can see nothing but blackness. While walking across the top of the wall, Shervane continually must look back in order to orient himself by the light of the fading Trilorne. Pretty soon, Trilorne can no longer be seen and Shervane continues on until he sees in the distance the faint light of a sun. Initially he surmises that the world must have two suns and that the other side of the world must have unknown civilizations and inhabitable lands. However, as he walks on, he finds Brayldon and the gigantic stairway waiting for him on the other side of the wall.

As Shervane's old teacher correctly theorizes, the world is similar to a sheet of paper with only a single side. By two-dimensional analogy, he takes a sheet of paper, twists it, and then joins the ends. The result is a cylinder that has a surface that travels first along the inside of the cylinder and then outside of it.

After this discovery, Brayldon and Shervane destroy the stairway with explosives. Though Shervane plays with the idea that there is an identical Shervane on the other side of the wall watching the explosion, he knows that there is only one and that the world merely folds back into itself.