How did the US discover the nuclear missile construction sites in Cuba?

The U.S. discovered the nuclear missile construction sites in Cuba through aerial reconnaissance. On October 14, 1962, a U-2 spy plane flew over Cuba and captured high-resolution photographs that revealed the presence of Soviet missile bases under construction. This intelligence prompted immediate analysis and discussions among U.S. officials, leading to the Cuban Missile Crisis as tensions escalated between the U.S. and the Soviet Union.