April 25 in Military History

A Mexican cavalry force attacked a US Army patrol under Captain Seth Thornton north of the Rio Grande, killing 11 American soldiers. President Polk used the incident to declare that Mexico had "shed American blood on American soil," leading Congress to declare war.

French diplomat Ferdinand de Lesseps broke ground at Port Said on the Suez Canal, a 120-mile waterway that would reshape global maritime trade and military logistics. Britain and France would fight to control the canal in 1956.

Flag Officer David Farragut's Union fleet passed the Confederate forts below New Orleans and compelled the surrender of the Confederacy's largest and most important city. The loss was a devastating blow to the Southern war effort and secured Union control of the lower Mississippi.

Allied forces landed on the Gallipoli Peninsula in Ottoman Turkey. The eight-month campaign cost over 250,000 Allied casualties and became the founding national myth for Australia and New Zealand.

Advance patrols of the US 69th Infantry Division met Soviet troops of the 58th Guards Division at Torgau on the Elbe River in Germany. The historic handshake effectively cut Nazi Germany in two and symbolized the Allied victory.

James Watson and Francis Crick published their paper on the double-helix structure of DNA in Nature, launching molecular biology. The work would eventually produce military forensic and biotechnology capabilities including forensic DNA identification used in later conflicts.

USS Nautilus (SSN-571), the world's first nuclear-powered submarine, began sea trials off Connecticut under Commander Eugene Wilkinson. The Nautilus would revolutionize submarine warfare and underpin US nuclear deterrence strategy.

Junior officers of the Portuguese Armed Forces Movement launched a military coup that overthrew the Estado Novo dictatorship in Lisbon. The nearly bloodless revolution ended 48 years of authoritarian rule and the Portuguese Colonial War.

British forces of Operation Paraquet recaptured the Falklands dependency of South Georgia from Argentine marines, including the capture of Argentine submarine ARA Santa Fe. The operation was the first territorial victory of the Falklands War.

US Army 3rd Infantry Division and 101st Airborne Division elements secured the Tuwaitha nuclear research facility outside Baghdad. Subsequent inspections revealed extensive looting of nuclear material containers that raised serious non-proliferation concerns.

US Pacific Command launched Joint Task Force 505 disaster relief operations after the 7.8-magnitude Gorkha earthquake devastated Nepal. C-17 Globemaster III, V-22 Osprey, and UH-60 Black Hawk aircraft flew into Tribhuvan International Airport within 72 hours.