What part of the chromosomes do the spindle fibers attach to in order to move the chromosomes around?

Spindle fibers attach to the chromosomes at a region called the centromere, which is the constricted area where sister chromatids are joined together. Specifically, the spindle fibers connect to protein structures called kinetochores that form on the centromere during cell division. This attachment allows the spindle fibers to exert forces that move the chromosomes during mitosis and meiOSis.