What is now Alaska has been home to various indigenous peoples for thousands of years; it is widely believed that the region served as the entry point for the initial settlement of North America by way of the Bering land bridge. The Russian Empire was the first to actively colonize the area beginning in the 18th century, eventually establishing Russian America, which spanned most of the current state. The expense and logistical difficulty of maintaining this distant possession prompted its sale to the U.S. in 1867 for US$7.2 million (equivalent to $140 million in 2021), or approximately two cents per acre ($4.74/km2). The area went through several administrative changes before becoming organized as a territory on May 11, 1912. It was admitted as the 49th state of the U.S. on January 3, 1959.[5]