How the richly varied cell-types in the human body arise from one embryonic cell is a biological marvel and mystery. We have mapped how human pluripotent stem cells develop into over thirty different human cell-types. This roadmap allowed us to efficiently and rapidly generate human liver, bone, heart and blood vessel progenitors in a Petri dish from pluripotent stem cells. Each of these tissue precursors could regenerate their cognate tissue upon injection into respective mouse models, with relevance to regenerative medicine. In addition to our interests in developmental and stem cell biology, we also harbor an emerging interest in deadly biosafety level 4 viruses, such as Ebola and Nipah viruses.