Most snake species lay external eggs. Always the contrarians, anacondas employ a method called ovoviviparity. This is a process in which a mother keeps the eggs inside of her body until they hatch. Thus, the anaconda actually gives live birth, in a process similar to the way mammals are born. Some anaconda litters can be as large as several dozen baby snakes, all born at once!
Here's a video of anacondas being born. Undeveloped eggs and stillborn baby snakes come out in the birthing process as well. Mom gets to eat these if she's hungry. Ah, the miracle of birth!
19 Totally Mind-Blowing Facts