Criminal groups are organized entities that engage in illegal activities. Two of the most well-known criminal groups are mafias and gangs. Mafias are typically structured hierarchically and have a strong focus on loyalty and secrecy. They are often involved in activities such as extortion, money laundering, and drug trafficking. Gangs, on the other hand, are usually less structured and more loosely organized. They are often involved in activities such as robbery, burglary, and drug dealing.