The wife of investment banker Harry C. Piper, Virginia Piper was abducted by vigilantes at her home in Minnesota in 1972.
After the ransom of US$1 million (more than $6 million today) was paid, she was found chained to a tree.
Thompson was the president of Firestone in 1973 when he too was kidnapped by the People's Revolutionary Army in Argentina.
The guerilla group asked for about US$3 million, which can be equaled to $18 million today. He was freed around two and a half weeks later.
Enrique Metz was an executive for Mercedes Benz who was based in Argentina. Metz was kidnapped by the guerrilla group Montoneros in 1975.
Montoneros ransomed Metz for US$5 million, which is worth around $24 million today.
Hearst was kidnapped by the Symbionese Liberation Army, a militant group who also orchestrated bank robberies. Hearst's father, Randolph Hearst (son of William Randolph Hearst Sr.), ended up giving out more than US$2 million worth of food (over $10 million's worth today).
Lockwood was a consultant on green business strategies, who was kidnapped by the Argentina's People's Revolutionary Army twice! The first was in 1973, with a ransom of US$2 million (nearly $12 million today).
The second time was in 1975, with a ransom of US$10 million (more than $48 million today).
The ransom was set at around US$77 million, which was paid. Kwok was then found alive in a wooden box in a village house. It's said that Kwok had a rivalry with his brothers, who didn't want to pay the ransom, which is around $122 million by today's standards.
The same gangster behind Walter Kwok's kidnapping also reportedly abducted Victor Li in 1996. Victor Li is the son of Hong Kong tycoon Li Ka-shing (pictured).
Jorge and Juan Born were stockholders in Bunge & Born, one of the biggest businesses in Buenos Aires. They were both kidnapped in 1974, with a steep ransom set at US$60 million.
The pair were abducted by Montoneros, but were freed nine months later after the ransom was paid. Today, the ransom is estimated to be worth $326 million.
See also: History's most famous examples of parricide
The most expensive ransoms ever paid
The prices we pay for the people we love
LIFESTYLE Crime
There are millions of ways to make money around the world. Holding loved ones ransom is probably one of the more corrupt jobs, but it has happened countless times across the globe. Click on to find out how much people are willing to pay, to see the people they love once more.