In which phase of the cell cycle does crossing over occur?

Crossing over is the process by which chromosomes are able to 'cross over' and exchange some of their genetic material during meiosis. The consequence of this is increase genetic diversity. Meiosis is the process of forming gametes (sperm and egg cells), during this process the number of chromosomes is reduced by half and only return to the full number (diploid) when gametes fuse in fertilisation.
Meiosis is split into phases going in the order:Prophase 1 - metaphase 1 - anaphase 1, telophase 1 - prophase 2 - metaphase 2 - anaphase 2 - telophase 2crossing over (also known as chiasmata) may occur during prophase one. during crossing over chromatids may break and may be reattached to a different chromosome. this increases the variability of gametes and the individuals they produce.