This comes courtesy Ben G.:
This video is about a lab in Florida that has the biggest magnet on the planet, so strong that it can levitate fruit! It is explained in the video that the way that these electro-magnets are able to be made so strong is by the incredible density of its coils. As well as the fact that a few of these coils are stacked within each other, amplifying the magnet. I thought this was interesting because I had no idea that you could levitate non-metal objects with magnets.