Vaginas — they’ve inspired monologues, and maybe even cave paintings, but science is only just beginning to unlock the organ’s many mysteries.

“We were worried about vaginas. We were worried what we think about vaginas, and even more worried that we don’t think about them,” reads the first act from American playwright Eve Ensler’s 2009 version of her episodic play, The Vagina Monologues

“There’s so much darkness and secrecy surrounding them — like the Bermuda Triangle. Nobody ever reports back from there.”

2006 study published in the Human Reproduction journal admitted that the anatomy of the vagina had been poorly studied. It says that until as recently as 10 years ago, much of what we know about the punani, or slang for vagina, was based on old observations made from a small number of cadaver dissections. But this is changing.

Here are five things you might not know about that place you passed through on your way into the world.

1. Your vagina is like an iceberg

The average kuku (in Setswana) is about 8cm, or about three-quarters the length of a cool drink can, says the  United Kingdom’s National Health Service.

In some ways, it makes the organ like an iceberg. The  United States Coast Guard says only about 10% of the floating ice chunks are visible above water. Despite what you may catch sight of on the outside, the vagina is a muscular tube running from the vaginal opening to the cervix. There’s also no one shape to the vagina, notes the Human Reproduction journal study.

While not an insurmountable length, the vagina is long enough to perhaps explain the frequency of lost tampons in emergency rooms, noted the textbook  Accident & Emergency: Theory into practice. The book recommends a good light and a speculum – or metal device used to open the vagina during examinations – for a quick and easy removal. The authors say these incidents are usually the result of sexual intercourse with a tampon in, the use of two tampons at once or breaks in the strings used to remove tampons.

2. It’s an ecosystem down there

The average woman is likely to have tens of thousands of organisms in her vagina, and most of these are naturally occurring.

For years we’ve known that women are biologically more susceptible to sexually transmitted infections than men. The United States Centres for Disease Control explain that the vagina’s lining is thinner and more delicate than the skin on a penis — and there’s more of it stretching along that 8cm canal. This makes it easier for bacteria and viruses to take hold in the female reproductive tract.

But we’re finding out more every day about how the bugs that hang out in a woman’s vagina affect her risk of infections such as HIV. In a study conducted among 120 South Africans living with HIV, researchers from the Centre for the Aids Programme of Research in South Africa found that one bacterium, Prevotella bivia, could drastically increase a woman’s risk of contracting HIV. They posit that the bug, which usually begins being present in women’s systems around the time of their first menstrual period, could account for about 40% of HIV infections in women.

Released at the International Aids Conference held in Durban in July, the study also found that when these bacteria flourish out of control, they’re usually accompanied by another partner in crime: Gardnerella vaginalis.

And there’s more bad news: G vaginalis also decreases the effectiveness of Tenofovir, one of the two drugs being used in an HIV prevention pill that is taken daily.

The good news? A simple test can detect unbalanced pH levels, which allow these bacteria to grow when the vagina’s ecosystem is out of whack, and the cure is simple and cheap.

3. Your vagina may want you to quit smoking

Vaginal infection caused by bacteria is a drag and, like the vagina, the cause of the bacteria overgrowth behind the condition remains somewhat of a mystery, says the Mayo Clinic, a non-profit organisation in the US. Many women are familiar with the bacterial vaginosis symptoms, which include discharge, itchiness and a fishy smell.

What can you do to avoid this? First, stop douching. Leave your vajayjay alone, advises the Mayo Clinic. Your vagina is self-cleaning. Stop making it angry.

You can also stop smoking. A preliminary 2014 study published in the BioMed Central Infectious Diseases journal found that smokers had lower levels of the good bacteria, lactobacillus, than non-smokers. Lactobacillus can help prevent vaginosis. While more research is needed, scientists speculate that quitting smoking could help prevent recurring bacterial vaginosis.

4. You and your vagina are like snowflakes

No two snowflakes are alike and the same can be said for vaginas. The UK National Health Service points out that  vaginas come in all shapes and colours. Imaging has revealed that vaginas can be egg-shaped or even, as one study noted, “pumpkin seed shaped”. They can be brown, light pink or even a deep red in colour. A woman’s labia, or the “lips” on the outside of the vagina, are equally unique. While some women are choosing to go under the knife for labiaplasty, plastic surgery that can resize or reshape the labia, the health service says larger or uneven labia are rarely a problem.

The National Health Service’s advice? Don’t judge your labia by another’s standards.

5. Like you, your vagina should hit the gym

Extra time on the treadmill isn’t just good for your cardio routine. The UK health department says normal exercise like walking and running strengthen your pelvic floor, which helps support your vagina and other organs such as the bladder and uterus. The Mayo Clinic advises that you work your pelvic floor muscle three times a day. These exercises can prevent urinary incontinence.

Not sure where these muscles are? Stop your flow of urine mid-stream in the loo. If you do, you’ll feel which muscles tighten. Once you have located them, contract them and holding this position for 10 seconds at a time, repeating this about 10 times in a row three times a day.

[This story was originally published on 22 August 2016]