Half of humanity knows, has known or will know how it feels to live inside a menstruating & ovulating body.
We ebb and flow like the tide, we change like the seasons, we're cyclical as the moon, plants and everything else in nature. The biology of our reproductive system is brilliantly sophisticated. The folklore around it is rich and full of wisdom. We're different every day, but we return to that same day and experience similarity. It has a pattern and inside that pattern is an insight to yourself: how you feel about what you eat, how you spend your days, who you spend it with, what you need, what you want.
It's a colorful, magical, brilliant reality. But it's not celebrated and it's rarely taught. We're ignoring it at best and hating it at worst - looking at centuries of ideologies to dominate over nature and female sexuality & fertility that *might be at fault here*.