What drives women to extreme acts?
"I had a pistol in my belt, a grenade in my pocket and TNT in my bag. I was a woman dressed in a fashionable way. I opened my bag for security but the man just saw my make-up and waved me through."
Leila Khaled was probably the most famous female hijacker in the world in the late 1960s - beautiful, dangerous and politically committed to doing whatever might further the Palestinian cause.
She featured in an iconic photo - sultry-eyed, a Kalashnikov at her side, headscarf carefully draped over her head.
She even subsequently resorted to painful plastic surgery to hide her famous face so she could carry on participating in hijack operations without being recognised.
But she was by no means the first woman to hit the headlines for using violence for political aims.
One of her role models was Zohra Drif, a female bomber during Algeria's war of independence from France in the 1950s.
In September 1956, she planted a bomb in the Milk Bar cafe in Algiers.
Among the victims was an elderly woman who lost her life and her five-year-old granddaughter whose leg was torn off.
The history of women and terror goes back further still.
Women played leading roles in the Russian 19th Century revolutionary movement whose activities marked the start of modern terrorism, some of them key members of a plot to kill Tsar Alexander the Second.
More recently women were prominent in Germany's Baader-Meinhof gang, Italy's Red Brigade, in the Provisional IRA in Northern Ireland and they swelled the ranks of the Tamil Tigers in Sri Lanka, where it is estimated that they accounted for a third of all fighters and a third of their suicide bombing squads too.
So what drives women to terrorism?
According to their own testimonies, like their male colleagues they often turn to violence out of a passionate political commitment.
Today Leila Khaled and Zohra Drif look back on what they did with pride.
They refuse to describe themselves as terrorists and still defend their causes as justified.
"My role was to hold arms and to fight like my people," says Khaled.
"Yes, we attacked innocent civilians," says Drif.
"But what is innocent in war? European civilians were occupying our country and we were fighting them. We were at war."
Born in Haifa in modern day Israel in 1944. Her family fled to Lebanon during the 1948 Palestinian exodus, leaving her father behind.
Joined the Arab Nationalist Movement at the age of 15.
On 29 August 1969, Khaled was part of a team that hijacked TWA Flight 840 on its way from Rome to Athens, diverting the Boeing 707 to Damascus. No-one was injured but the plane was blown up after the hostages had disembarked.
On 6 September 1970, Khaled and Patrick Arguello, a Nicaraguan-American, attempted the hijack of El Al Flight 219 from Amsterdam to New York City, but the attack was foiled by Israeli sky marshals. The plane was diverted to Heathrow airport in London, and Khaled was taken into custody.
She was released a month later in exchange for hostages taken in a further hijacking.
Leila Khaled also insists she was under instructions not to hurt anyone, though she was certainly prepared to go to the brink.
When she hijacked an American TWA jet in 1969, she threatened to detonate her grenade unless the pilot agreed to change course for Damascus.
"I had to keep my grip on the grenade for six hours because I had taken the pin out," she says.
For some women getting involved in terrorism could also be empowering.
Mairead Farrell was one of the most high-profile women in the Irish Republican movement until her death in Gibraltar in 1988 at the hands of British Special Forces.
A year before her death she recalled in an interview the women's "dirty protest" she led while serving time in Armagh jail for her part in an IRA bomb plot.
She said that while the initial aim was to support male prisoners, the protest also made the women more aware of their political status and their right to be activists as well as wives and mothers.
"It became our joke, the mother image," she said.
"Our joke was 'Mother Ireland - get off our back!' because it didn't reflect what we believed in… we'd moved on from that."
In Sri Lanka, Mia Bloom, author of a study of women terrorists called Bombshell, says she was struck by the level of dedication in female Tamil Tiger fighters.
She says that though they often joined in the wake of a personal tragedy, they grew more political as they studied the roots of the conflict, and would compete with men and each other to become suicide bombers.
There is no doubt that women terrorists have been highly effective - slipping through checkpoints more easily, getting closer to their targets than men, and able to hide weapons or suicide belts under their clothing.
New security checks
That may be changing.
Some West African countries, including Chad, Gabon and parts of Cameroon, have recently started banning the wearing of full face veils in public, following a spate of suicide bombings by women in burkas.
Female bombers also tend to draw more publicity.
Experts note that a decision to put women on the front line is often a sign that a terrorist movement is in trouble, running out of male fighters or otherwise under pressure.
High-profile bombings carried out by women are a way to magnify the impact, because people tend to find the idea of a woman being behind a brutal killing so much more horrific and "unnatural".
In Russia, after President Putin launched a campaign against Chechen terrorists from 1999 onwards, female suicide bombers became so prevalent they were known as "Black Widows" - a reference to their black clothing, and because they seemed to be acting out of revenge for lost husbands, sons and brothers.
But the Chechen example also highlights a paradox.
How far were these women driven not just by revenge, but also despair that they had nothing else to live for?
And if so, how many were cajoled or coerced into taking such drastic action?
During the Moscow Theatre siege of 2002, it was the Chechen male terrorists who ran the operation, while their female companions wore the suicide vests and carried out their orders.
End to shame
In Sri Lanka too there is evidence that some women turned to suicide bombing after they had been raped and wanted to end the shame to themselves and to their families.
So what about the young women travelling to Syria to become "jihadist brides" to fighters of so-called Islamic State (IS)?
There is no sign yet that they themselves are carrying out attacks.
But some of the online postings under their names can be bloodthirsty and gory, revelling in the terror acts of others.
Erin Saltman, of the Institute of Strategic Dialogue, who has been tracking some of the women online, says the reasons for being attracted to IS seem to be multiple: sisterhood, belonging, romance and utopia building, and a promise of empowerment from a community which promises not to sexualise you - even though the reality may turn out to be very different once they arrive in Syria or Iraq and find themselves in a tightly controlled and restricted environment.
But the main lesson those who study this phenomenon seem to draw is - don't oversimplify.
As with male terrorists, the reasons women join up are multiple and complex, and they are frequently not innocent or passive participants - however uncomfortable that may be to acknowledge.
Hear Bridget Kendall's documentary Women of Terror on Radio 4 on 3 August at 2000 BST.
This article first appeared in Radio Times.