Black holes may potentially serve as portals to other universes or contain entire universes within them, but current knowledge limits this to speculation. Both black holes and wormholes exhibit similar local spacetime curvature, making it impossible for outside observers to distinguish between the two. Frame dragging, associated with rotating black holes, is not typically applied to wormholes, though it is a measurable phenomenon in massive rotating objects. The discussion highlights the intriguing possibility of parallel universes being accessible through black holes. Ultimately, the nature of black holes and their relationship to other universes remains an open question in theoretical physics.