In the Womb: Animals is an unprecedented two-hour world premiere special that takes you inside the hidden world of animal pregnancy. Using state-of-the-art visual effects, computer graphics and real-time, moving 4-D ultrasound imagery, we can see inside the unique world of animal fetal development in a way never before possible. For the first time, these pictures shed light on how an elephant, a dolphin and a dog develop in the womb. - National Geographic Channel.
But even the pictures on the site are pretty cool. And here is an extra cool pic of an elephant.