Kaluza-Klein monopole

By adding the trivial term -dt2 one can convert the four-dimensional (positive definite) Newman-Unti-Tamburino line element into a static solution of the five-dimensional vacuum Einstein equations. Interpreted a la Kaluza and Klein, the solution describes a monopole with a charge-to-mass ratio of √2 in rationalized Planck units. Although it is a perfectly regular five-geometry it appears singular from a four-dimensional perspective