Magnetic fields are invisible to the human eye but they are extremely powerful. Magnetic fields are produced by the motion of electrical charges, and every magnet has two poles - north and south. The north pole end of one magnet will repel the north pole end of another magnet when placed close together. But as we all know, if you place the opposite poles near one another, the magnets will stick together, and in this case, totally destroy whatever is in between!
Want to learn more about magnetic fields? Check out these videos:
Visualizing The Sun's Magnetic Field
What Will Happen When Earth's Magnetic Poles Reverse?