May 5, 1862 – Mexican troops under General Ignacio Zaragoza, outnumbered three to one, defeat the invading forces of Napoleon III in the battle of Pueblo which forever after is celebrated as a national holiday; Cinco de Mayo (Fifth of May).
May 5, 1961 – Alan Shepard becomes the first American in Space. His Freedom 7 spacecraft travelled in space for 15 minutes and 28 seconds. In a subsequent flight in 1971 he would become the fifth person to walk on the moon.
May 6, 1937 – The German airship Hindenburg bursts into flames and crashes while mooring at Lakehurst, New Jersey killing 36 of the 97 passengers and crew and effectively ending commercial airship travel.
May 10, 1869 – The transcontinental railroad in the U.S. became a reality with the driving of the ceremonial golden spike at Promontory Point, Utah joining the Central Pacific and Union Pacific railroads.