2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/154054We review, in a historical perspective, some results about black hole spacetimes with a regular center. We then see how their properties are realized in a specific solution that recently appeared; in particular we analyze in detail the (necessary) violation of the strong energy condition.LaTeX, 36 pages, 10 figures. To appear in the proceedings of "BH2, Dynamics and Thermodynamics of Blackholes and Naked Singularities", May 10-12 2007, Milano, Italy (conference website: http://www.mate.polimi.it/bh2)General Relativity and Quantum Cosmologytext