In this Nature paper, Ashley Moffett and colleagues describe 3D human trophoblast culture systems (or "mini-placentas") that organize into villous-like structures and secrete various placenta-specific factors. These organoids can differentiate into extravillous trophoblast cells, an important feature of placentation, and transcriptional and methylome profiling show that they resemble first trimester trophoblasts. In the future, the mini-placentas could provide new insights into the human placenta and pregnancy disorders related to placental dysfunction.