1. Lewis and Clark Expedition: On May 14, 1805, the Lewis and Clark Expedition arrived at the confluence of the Missouri and Yellowstone Rivers in what is now Montana. This site would become an essential stopover for fur traders and explorers in the decades to come.

2. Statehood: Montana officially became a state on November 8, 1889, but its journey towards statehood began several years earlier. On May 14, 1884, the Territory of Montana held its Constitutional Convention in Helena, which paved the way for statehood.

3. Fort Peck Dam: Construction on the Fort Peck Dam, the largest dam on the Missouri River, began on May 14, 1933. The dam was a significant part of the New Deal era public works projects that helped put people to work during the Great Depression.

4. Bobcat Stadium: Bobcat Stadium, home to the Montana State University Bobcats football team, opened on May 14, 1973. The stadium has a seating capacity of over 17,000 and has hosted many significant events, including the NCAA Division I Football Championship Game.

5. Marias Massacre: On May 14, 1870, a group of US Army soldiers attacked a camp of Blackfoot Indians along the Marias River, killing over 170 people, mostly women and children. This event, known as the Marias Massacre, was one of many conflicts between Native Americans and settlers in Montana during the late 19th century.