What happened on 31 May?

9 events from the Ever-When timeline, ranked by how much they mattered.

1. 1916 Battle of Jutland Largest naval battle of WW1; tactical German success, strategic British command of the sea.
2. 1819 Born: Walt Whitman American poet; Leaves of Grass.
3. 1921 Tulsa race massacre White mobs destroy the prosperous Black Greenwood district of Tulsa.
4. 1915 First strategic bombing of London German zeppelins bomb London — first major civilian bombing campaign.
5. 1223 Battle of the Kalka River A Mongol reconnaissance force under Subutai routs a Rus'-Cuman army, the first clash between the Mongols and the Russian principalities.
6. 1961 South Africa leaves the Commonwealth Rather than face the newly multiracial Commonwealth's condemnation after Sharpeville, Verwoerd withdraws and declares a republic. The laager mentality is now foreign policy — and t
7. 1910 Union of South Africa British dominion uniting Cape, Natal and the former Boer republics.
8. 1902 End of the Second Boer War The Treaty of Vereeniging ends the war, bringing the Boer republics under British rule and leaving a bitter Afrikaner legacy.
9. 2002 2002 FIFA World Cup The first World Cup in Asia, co-hosted by South Korea and Japan, with South Korea's run to the semi-finals electrifying the continent.