Births on July 20

Otto Blumenthal, German mathematician and academic (d. 1944)

Ludwig Otto Blumenthal (20 July 1876 – 12 November 1944) was a German mathematician and professor at RWTH Aachen University.

2 Feb

Major League Baseball
The National League of Professional Baseball Clubs of Major League Baseball is formed.
10 Mar

Alexander Graham Bell
The first successful test of a telephone is made by Alexander Graham Bell.
22 Apr

MLB
The first game in the history of the National League was played at the Jefferson Street Grounds in Philadelphia. This game is often pointed to as the beginning of the MLB.
4 Jun

First Transcontinental Railroad
An express train called the Transcontinental Express arrives in San Francisco, via the First Transcontinental Railroad only 83 hours and 39 minutes after leaving New York City.
25 Nov

Battle of the Little Bighorn
American Indian Wars: In retaliation for the American defeat at the Battle of the Little Bighorn, United States Army troops sack the sleeping village of Cheyenne Chief Dull Knife at the headwaters of the Powder River.