The cornerstone was laid on July 4, 1848. Work stopped from 1854 until 1877 because of money problems and the Civil War, and the stone was finished in 1884. It was dedicated on February 21, 1885 and opened to the public on October 9, 1888.
Look about a third of the way up. The lower part is a whiter marble and the upper part is warmer in color, because different quarries supplied the stone before and after the pause.
The tip is an aluminum cap cast in 1884. At the time it was the largest piece of aluminum ever cast. A 5.8 magnitude earthquake cracked the monument in 2011, and it reopened in 2014 after $15 million of repairs.

