This picture caught my eye and was so cool I just couldn’t resist posting about it. This is a liquid called FerroFluid. What you are looking at is a 3-D representation of a magnetic field revealed by this magnetic fluid. To get a really good look at this, check out this Google Video of Sculptures with Ferrofluid.
The fluid is basically made up of very small (nano-small) particles of ferromagnetic material. Ferromagnetic items are the same type of magnets you would find on your refrigerator, except these are obviously much smaller. They are usually suspended in water, and something interesting is that although they are a common type of magnet, they do not retain their magnatism on their own, only when an external magnatism is applied. That is what gives them the ability to display the external magnetic field so well.
Ferrofluids are not uncommon in different industries as they become less magnetic as they heat up. This makes them great for use as a heat sink, where the cooler parts of the fluid move toward the hotter part of the magnetic force.
There is a good wiki page that has more information and applications for ferrofluid.