During mitosis, one of the most recognisable stages is metaphase. Chromosomes, attached to kinetochore microtubules, line up in a single plane midway between the spindle poles. Tension from the microtubules makes the chromosomes jiggle back and forth until the cell is ready to pull the daughter chromatids apart. Nikon's MicroscopyU filmed this in pig kidney epithelial cells with fluorescent labels on microtubule ends and chromosomes, using laser scanning confocal microscopy.
via Mitosis in Pig Kidney Epithelial Cells | Nikon MicroscopyU (archived)