1. On June 18, 1907, the state of Idaho declared the white pine its official state tree. This majestic tree once covered vast areas of northern Idaho but was nearly wiped out by logging in the early 20th century. The designation as the state tree helped raise awareness of the need for conservation and protection efforts.

2. In 1923, the City of Boise officially opened its new municipal airport on June 18. The airport, located on 270 acres of land on Gowen Field, was a major transportation hub for the region and played a key role in connecting Idaho with the rest of the country.

3. On June 18, 1930, the Idaho National Guard was mobilized in response to a massive forest fire that had broken out near the town of Nezperce. The fire burned over 100,000 acres of land and destroyed numerous buildings before it was finally contained.

4. In 1959, the first atomic-powered submarine, USS Nautilus, made a stop in the city of Pocatello on June 18 as part of a nationwide tour. The Nautilus was a groundbreaking vessel that demonstrated the potential of nuclear power as a propulsion source for ships and submarines.

5. On June 18, 1988, the world-famous Sun Valley Ice Show celebrated its 50th anniversary with a special performance featuring Olympic figure skaters and other top performers. The Sun Valley Ice Show has been a summer staple in the resort town since its inception and has showcased some of the best skating talent in the world.