. >> only 50 people survived sobibor, philip among them.risoners were brought here and systematically murdered in gas chambers on an industrial scale. he took part in a rebellion, and he and his brother managed to flee, but it was impossible to lead a normal life after his experiences in sobibor. he later married and had children, but the death camp left its stamp on him permanently. >> if by chance somebody survives, they are witness and tell the world about this place, so here i am, a living witness of the horror of history. >> excavating the site's meticulous work. the machinery of mass murder ground to a halt in sobibor after just a year and a half. the nazis leveled it in an attempt to eliminate all traces of what had gone on here, so it was all the more surprising when archaeologists uncovered remnants of the walls. philip wants to know about everything they have found. >> this is the outer wall of one of the gas chambers. >> did you find any showers? >> no, not yet. >> they dismantled it. >> it is taken away. >> if the research team