Pick one for us or just read em and remember or learn about history. 

https://en.wikipedia.org/wiki/March_30

1867 – Alaska is purchased from Russia for $7.2 million, about 2-cent/acre ($4.19/km²), by United States Secretary of State William H. Seward.

https://www.loc.gov/rr/program/bib/ourdocs/alaska.html

 Treaty with Russia for the Purchase of Alaska

Portrait                          of Secretary of State William H. Seward, officer of                          the United States Government. Brady National Photographic Art Gallery (Washington,                          D.C.), photographer. [Between 1860 and 1865]. Prints                          and Photographs Division. Reproduction Number: LC-DIG-cwpb-04948

On March 30, 1867, the United States reached an agreement                    to purchase Alaska from Russia for a price of $7.2 million. The                    Treaty with Russia was negotiated and signed by Secretary                    of State William Seward and Russian Minister to the United                    States Edouard de Stoeckl. Critics of the deal to purchase                    Alaska called it "Seward’s Folly” or “Seward’s                    Icebox." Opposition to the purchase of Alaska subsided                  with the Klondike Gold Strike in 1896.