STOCKHOLM, Sweden: 'Get down to the floor! The party begins!' Shouting in English, Jan-Erik Olsson walked into a Stockholm bank on August 23, 1973, high on drugs, agitated and waving a submachine gun.
So began a hostage drama that would go on to last six days, and birth the term 'Stockholm Syndrome' — a concept now known around the world whereby captives develop an emotional bond with their captors.
Olsson, known by his nickname 'Janne,' took four employees hostage — three women and one man.
Police and media quickly swarmed the square outside Kreditbanken, with snipers perched in surrounding buildings, their weapons pointed at the bank.
Olsson used two hostages as human shields and threatened to kill them.
'Afterwards, I've often thought of the absurd situation we found ourselves in,' recalled hostage Kristin Enmark, then 23, in her book 'I Became the Stockholm Syndrome.'
'Terrified and stuck between two death threats, on one side the police and on the other the robber.'

Olsson made several demands, asking for three million kronor (almost $700,000 at the time), and that Clark Olofsson, one of the country's most notorious bank robbers in prison at the time, be brought to the bank.
To calm things down, the Swedish government agreed.
The entire country was mesmerized by the unfolding drama, one of the first major news events broadcast live on Swedish television.
'When Clark Olofsson arrived, he took control of the situation, he was the one who did the talking with the police,' recalled now 73-year-old Bertil Ericsson, a news photographer who covered the crisis, in an interview with AFP.
'He had a lot of charisma. He was a good speaker.'
Olsson calmed down as soon as Olofsson arrived. And Kristin Enmark quickly saw in Olofsson a savior.
'He promised that he would make sure nothing happened to me and I decided to believe him,' she wrote.
'I was 23 years old and feared for my life.'
She spoke on the phone to authorities several times during the hostage drama, shocking the world when she came out in defense of her captors.
'I'm not the least bit afraid of Clark and the other guy, I'm afraid of the police. Do you understand? I trust them completely,' she told then prime minister Olof Palme in one phone call.