Venzuelan President Nicolás Maduro holds up the passports of two Americans detained in Venezuela in early May.
Handout/EPA
US denies backing failed raid to remove Venezuela's Nicolás Maduro – but it has a long history of sponsoring private armies elsewhere.
kirill_makarov via Shutterstock
Guns for hire are back in business – and they're making war even more dangerous.
British army conducts anti-poaching training in Nanyuki, Kenya.
Dai Kurokawa / EPA
Protecting rhinos and fighting terrorism are both noble causes, but there isn't much evidence of a link between the two.
Who are you going to call?
EPA/Felipe Dana/AP/World Press Photo
IS has proved very adept at fending off massive conventional forces – but that doesn't mean crack private security teams would do any better.
Orwell (tallest, centre) in Huesca, Spain in 1937.
Hoover Institution Archives/Harry Milton Papers
Comparisons of foreign volunteers in Syria to the International Brigades of Spain are apt, but not for the reasons you think.
The aftermath of a Libyan militia’s clash with Islamic State.
Reuters
Mercenaries and private armies have always been controversial – but are they really any worse than regular armies?
The Nigerian army patrols in Chibok, Borno State. There are reports South African mercenaries have joined them.
Henry Ikechukwu/EPA
South Africans have a reputation for being among the best mercenaries in the world. It's no wonder Nigeria is turning to them.