Signed in the Villa de Guadalupe Hidalgo near Mexico City, the treaty ended two years of war and ceded roughly 525,000 square miles — present-day California, Nevada, Utah, and parts of Arizona, New Mexico, Colorado, and Wyoming — to the United States for $15 million. Mexico lost roughly half its national territory. The treaty also promised citizenship and property protections to Mexican residents in the ceded lands, promises frequently broken in the decades that followed.

Launched from Cape Canaveral atop a Juno I rocket, Explorer 1 became the first successful American satellite, arriving in orbit in the early hours of February 1 by U.S. time (February 1 in the U.S., but confirmed in orbit by February 3 announcements in some press cycles). Its Geiger counter, designed by physicist James Van Allen, detected the radiation belts encircling Earth that now bear his name, transforming the mission from a Cold War morale boost into a genuine scientific breakthrough.

Buddy Holly, tired of the tour bus's broken heater, chartered a small plane to reach the next show in Fargo. Shortly after takeoff from Mason City, Iowa, the pilot, disoriented in a snowstorm and not certified for instrument flying, flew the plane into the ground. All four aboard died instantly. Don McLean later immortalized the tragedy as "the day the music died" in his 1971 song "American Pie."

Following Cuba's turn toward the Soviet bloc and the failed Bay of Pigs invasion, Kennedy expanded existing restrictions into a comprehensive embargo banning nearly all trade with Cuba. The order, issued under the Foreign Assistance Act, effectively sealed off the island from American commerce. Decades later, remnants of the embargo remained among the longest-running trade sanctions in modern history, still debated in U.S. politics into the 21st century.