The first inhabitants of the land now called Maine probably arrived around 12,000 years ago. Over the course of this land’s history, Native American tribes such as the Maliseet, Passamaquoddy, Abenaki, and Penobscot lived on the land. When the American Revolution was over, Maine joined the United States as part of Massachusetts. But many Maine settlers wanted to have their own state. In 1820 Maine separated from Massachusetts, becoming the 23rd state in the union. This was done as part of the Missouri Compromise, a deal that admitted Missouri as a state as well. Several Native American tribes still exist in Maine, including descendants of the original Passamaquoddy, Maliseet, and Penobscot tribes. Maine was given the nickname the Pine Tree State in honor of its many white pine trees, which are the biggest eastern conifers in the United States. The biggest state in New England, Maine is bordered by Canada in the north and east, the Atlantic Ocean in the south, and New Hampshire in the west. The land can be divided into three geographic areas. Moose, black bears, bobcats, white-tailed deer, and Canada lynx can be found in Maine. Bald and golden eagles, ospreys, great gray owls, and roseate terns are a few of the state’s many birds. Maine is also filled with black oaks, sugar maples, black walnuts, and American elms, in addition to its white pine trees. About 90 percent of Maine is covered in forests, so it’s no wonder that trees are among Maine’s most important natural resources. Some trees are used for their wood and others for their maple syrup. The state also mines semi-precious stones including some of the world’s best tourmaline crystals. Maine produces a lot of gravel and limestone as well.