  We review the construction of a particular soliton-type solution of the
classical Einstein and matter-field equations. This localized finite-energy
static classical solution can be interpreted as a single spacetime defect
embedded in Minkowski spacetime and may give rise to several new effects. For a
Skyrme-type theory with small enough matter-field energy scale compared to the
Planck energy scale and for a sufficiently small defect length scale, the
existence of a globally regular solution requires a negative active
gravitational mass, so that the defect repels a distant test particle
("antigravity"). There also exist "stealth defects" which have a vanishing
asymptotic gravitational mass. These stealth defects are, however, not entirely
invisible as they bring about a new type of gravitational lensing.
