The 23rd Amendment was ratified, allowing residents of Washington, DC to vote in US elections.
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NASA's Mariner 10 became the first spacecraft to reach Mercury.
Europe's longest bridge officially opened in Lisbon, Portugal.
Beethoven performed in person for the first time.
US President Herbert Hoover installed the White House's first telephone.
China's famous Terracotta Army was uncovered by a group of farmers near Xi'an, China.
