Prophase: The chromosomes "condense," or become so tightly wound that you can see them under a microscope. The membrane around the nucleus, called the nuclear envelope, disappears. Spindles also form and attach to chromosomes to help them move.
Metaphase: The chromosomes line up in the center, or the equator, of the cell. The chromosomes line up in a row, one on top of the next.
Anaphase: The two sister chromatids of each chromosome separate as the spindles pull the chromatids apart, resulting in two sets of identical chromosomes.
Telophase: The spindle dissolves and nuclear envelopes form around the chromosomes in both cells.