Body's Cavity's

So many organs in such a small space, organized in most effective and functional way. In the abdominal Cavity; large intestines, small intestine, kidneys, pancreas, liver, reproductive organs, stomach, bladder...how does it all fit? Jelly-like, hard and squidgey, I look at a liver and can know more about the shape and size of  my own but still can't imagine it being functional. How does it work ? It just does.