4. Ransom

Kidnapping for ransom (of both children and adults) is most common in countries with a high crime and corruption level, a poorly resourced police force, a weak judicial system, and a history of social or political instability, according to a study conducted in South Africa for the Institute for Security Studies.

5. Dozens of kidnappings

The Gauteng police deal with over a dozen kidnappings for ransom each month, according to the study mentioned above. Most of these kidnappings involve children.