The Transportation Security Administration (TSA) is a U.S. government agency responsible for ensuring the safety and security of the nation's transportation systems. Established after the events of September 11, 2001, the TSA focuses primarily on airport security, screening passengers and baggage to prevent dangerous items from being brought onto airplanes. In addition to airport security, the TSA also oversees security for other modes of transportation, including railways and public transit. The agency implements various security measures, such as advanced screening technologies and passenger identification checks, to protect travelers and maintain the integrity of the transportation network.