Arizona states of Sonora and Baja California. Arizona is the 48th state and last of the contiguous states to be admitted to the Union, achieving statehood on February 14, 1912, coinciding with Valentine's Day. Historically part of the territory of "Alta California" in New Spain, it became part of independent Mexico in 1821. After being defeated in the Mexican–American War, Mexico ceded much of this territory to the United States in 1848. The southernmost portion of the state was acquired in 1853 through the Gadsden Purchase. Southern Arizona is known for its desert climate, with very hot summers and mild winters.
Referendums related to the European Union Union. Austria, Sweden, and Finland were admitted as members of the EU, acceding on 1 January 1995. Two countries held referendums on the ratification of the treaty of Amsterdam. The 2004 enlargement of the European Union involved ten candidate states, eight from Central and Eastern Europe, and the Mediterranean islands of Malta and Cyprus. In 2003, referendums on joining the EU were held in all these nations except Cyprus. Since the results were in favourable in all cases, all ten candidate countries were admitted as members of the EU, acceding on 1 May 2004. Denmark and the United Kingdom received