Iowa became the 29th state to join the United States of America.
British astronomer William Lassell discovered Neptune's largest moon, Triton.
Anesthetic was used for the first time on a dental patient by Dr. William Morton.
Inventor Elias Howe was awarded the patent for the lockstitch sewing machine.
The longest papal reign began when Pope Pius IX was elected.
Baltimore and Philadelphia were linked up by telegraph.
US President James K. Polk asked Congress to declare war on Mexico.
The Thornton Affair, a skirmish between American and Mexican soldiers in Texas, started a chain of events that led to the Mexican-American War.
The first Mormon Pioneers left their homes in Nauvoo, Illinois, and began the long trek to the Salt Lake Valley.
