In 1827, Baltimore chartered the Baltimore & Ohio Railroad. The first line opened in 1830, providing service to Ellicott’s Mills (now Ellicott City). The B&O was the first railroad to carry passengers and freight. (Baltimore Sun photo, 1941)
1849: The ship California arrived at San Francisco, carrying the first of the gold-seekers.
1854: About 50 slavery opponents met in Ripon, Wis., to call for creation of a new political group, which became the Republican Party.
1953: Scientists James Watson and Francis Crick discovered the double-helix structure of DNA, the nucleic acid that contains genetic instructions for all known living things.
1983: The final episode of “M*A*S*H” aired on CBS; it was the most-watched television program in history for nearly 27 years, until being supplanted by Super Bowl XLIV in 2010.
Compiled by Laura Lefavor and Paul McCardell.