Hauntings exist all over the world, but there are a few locations with sordid pasts and dark histories that are especially sinister and purported to be doorways to the spirit underworld. In Travel Channel’s new series, “Portals to Hell,” premiering on Friday, April 19 at 9 p.m. ET/PT, television personality and executive producer Jack Osbourne, and paranormal researcher and investigator Katrina Weidman, join forces to explore this phenomenon, investigating each haunted location in search of irrefutable evidence that a spirit world exists, and death is not the end.