Authorities are trying to identify 22 women murdered in Belgium, Germany and The Netherlands over the last few decades.

Most of the murders are considered cold cases involving women who died 10, 20, 30 or even 40 years ago, according to Interpol, which launched a public campaign on Wednesday to name the women.

"Despite extensive police investigations, these women were never identified, and evidence suggests they could have come from other countries. Who they are, where they are from and why they were in these countries is unknown," Interpol said.

"Someone, somewhere, knows something which can help identify these women. Just one piece of information could be the missing link," Interpol Secretary General Jürgen Stock said on his official Twitter account as the campaign launched.

For the first time, as part of the campaign called "Operation Identify Me," Interpol has published so-called Black Notices about each victim, which include facial reconstruction images, information about personal items, clothes, jewelry, tattoos and pictures of the areas where the bodies were found.

"If you remember a friend, family member or colleague who suddenly disappeared, please take a look and contact the relevant national police team via the form on each page if you have any information about any of them," Interpol said.

'The woman in the well'

As the name of each woman is unknown, the cases are described by other characteristics and numbered. "The woman in the well" is the first unsolved murder.

In 1991, the body of a woman was found in a rainwater well on the grounds of a cottage near Leuvensebaan in Belgium, about 30 kilometers (18.6 miles) northeast from Brussels. Her body may have been in the well for up to two years, according to Interpol.

The woman is believed to have been between 30 and 55 years old when she was found, and 1.54 meters toll. She wore a distinctive t-shirt with black vertical stripes and a summer print. "The woman also wore dark plaid shorts, beige/brown knitted cardigan and a plastic or horn ring," Interpol said.

Interpol has also published images of the cottage and newspaper articles and asks the pubic to contact Belgium national police with any information about the case.

'The woman with the flower tattoo'

Another case involves the murder of a woman who had a flower tattoo on her left forearm. Under the black flower with green leaves is written "R'NICK."

In 1992, the body of the woman was found against a grate in the water of the Groot Schijn river near Ten Eekhovelei in Antwerp, Belgium, Interpol said.

"The woman had been killed by violence. To date, her identity is unknown," Interpol said.

She is believed to have been between 20 and 50 years old, about 1.70 meters tall. "She was light-skinned and had mid-length dark hair," Interpol said. She wore a t-shirt with the inscription 'SPLINTER' and "1990," dark blue Adidas training trousers with three green stripes and dark walking shoes.

Authorities are urging anyone who may have information about the woman to contact Belgium national police.

Belgium, German and Dutch police are working with Interpol on finding more information about the women. "The woman with the bracelet," "the woman by the motorway," "the woman on the boat," "the woman with the flower skirt" and "the woman in men's clothing" are how authorities are naming some of the other unidentified women.

Details about each woman and "Operation Identify Me" have been published on the Interpol website. "They are someone's friend, sister, cousin, daughter or mother. And they matter," Interpol said.