If you take a look at your hand, you’ll see something solid. It looks solid, anyway. The atoms that make up your hand aren’t that close together, though. If we could shrink ourselves down so small that atoms looked like trees, the inside of your hand would look like this forest. The atoms aren’t jammed together, they’re just loosely bound together. Those three trees in the foreground might be a water molecule. When we touch a table, the cloud of atoms in our hand interacts with the atoms of the surface. The two clouds don’t interact much because the bonds between the respective molecules is strong.
Still, there is quite a bit of… nothing inside all of us.