1896: The first commencement of Phoenix Union High School is held at the Phoenix Opera House. Keynote speaker John E. Merriam talked on "What Electrical Science is Doing for the World."

1910: It is announced that Picacho Mine, which sat idle in the Cababi Mountains for many years, would reopen.

1929: A majority of 800 Tucson voters approve the sale of $625,000 in bonds. Some will be used to build a controversial Broadway tunnel.

Want to share an important event from Tucson's history? Email it to krumore@azstarnet.com.