There are some researchers who believe that quantization of gravity means taking the sum over all topologies from the viewpoint of the path integral method. In two and three dimensions, there are no dynamical degrees of freedom in the gravitational field, thus taking the sum over topologies may be significant, but in four dimensions, that is not the main issue, the gravitational field dynamics is much more important. Still, spacetimes with special topologies may contribute to the physics of the early universe.