Superspace

Superspace was the name given by Spock to a universe visited by the USS Enterprise (NCC-1701) in 2267.

The universe of superspace was inhabited by three known races: the humanoid creators of a war machine; the alien invaders the machine was used against; and one which destroyed the machine centuries later.

In 2267, the USS Enterprise (NCC-1701) was drawn into superspace when the neutron star Nymyn underwent gravitational collapse and became a black hole. After saving the underground city Caeminon from the creations of the war machine, the Enterprise crew returned to their own universe through another collapsing star.