Smuggling is the illegal importation or exportation of goods, usually for monetary gain. It is a form of transnational crime, typically involving the illegal transportation of goods across international borders. It is sometimes referred to as contraband smuggling. Types of smuggling include drug smuggling, human trafficking, arms smuggling, illegal immigration, and wildlife trafficking. Smugglers may use various methods to evade detection, including the use of secret compartments, false documents, bribery, and the use of intermediaries. Smuggling is often associated with organized crime.