Confederate General Joseph E. Johnston, opening the way for the siege of Vicksburg. May 17 After a 2-month siege, the French army of Bazaine takes Puebla, Mexico. The opening of Salon des Refusés in Paris draws attention to paintings by avant-garde artists, notably Manet's Le Déjeuner sur l’herbe. May 18 – American Civil War: The siege of Vicksburg begins (ends July 4, when 30,189 Confederate men surrender). May 21 American Civil War: The siege of Port Hudson, Louisiana, by Union forces begins. The General Conference of Seventh-day Adventists is formed in Battle Creek, Michigan. May 23 – Ferdinand Lassalle founds the (General German Workers' Association, ADAV), the first socialist workers party in Germany. May 28 – American Civil War – The 54th Massachusetts, the first African-American regiment, leaves Boston to fight for the Union. May 31 – The first Prix de l'Arc de Triomphe horse race is held. June 7 – French intervention in Mexico: French forces enter Mexico City. June 9 – American Civil War: The Battle of Brandy Station, Virginia, ends inconclusively. June 12 – The Arts Club is founded by Charles Dickens, Frederic Leighton and others in Hanover Square, London. June 13 – Samuel Butler's dystopian article "Darwin among the Machines" is published (under the pen name Cellarius) in The Press newspaper in Christchurch, New Zealand; it will be incorporated into his novel Erewhon (1872). June 14 – American Civil War – Second Battle of Winchester: A Union garrison is defeated by the Army of Northern Virginia, in the Shenandoah Valley town of Winchester, Virginia. June 17 – American Civil War: The Battle of Aldie in the Gettysburg Campaign ends inconclusively. June 20 – West Virginia is admitted as the 35th U.S. state. July–September July – First successful test of the CSA hand-propelled submarine H. L. Hunley. July 1 – Slavery is abolished in the Dutch colonies of Suriname (independent from 1975) and Curaçao and Dependencies. July 1 – The Kingston loop line of the London and South Western Railway opens. July 1–3 – American Civil War: Battle of Gettysburg – Union forces under George G. Meade turn back a Confederate invasion by Robert E. Lee in the largest battle of the war (28,000 Confederate casualties, 23,000 Union). July 4 – American Civil War: Siege of Vicksburg – Ulysses S. Grant and the Union army capture the Confederate city Vicksburg, Mississippi, after the town surrenders, following a