The US Department of Homeland Security exists to keep America safe. Created in the wake of the 9/11 terrorist attacks, the department is devoted to keeping the US safe from natural and man-made disaster. Its activities include domestic nuclear detection, intelligence coordination, and protection of high-level government officials. The department's structure includes agencies for citizenship and immigration services, customs and border protection, emergency response and recovery (FEMA), and science and technology research. The US Department of Homeland Security has more than 240,000 employees and an annual budget of more than $55 billion.