1806    Pike expedition: United States Army Lieutenant Zebulon Pike begins an expedition from Fort Bellefontaine near St. Louis, Missouri, to explore the west.

1908    The Wright Flyer flown by Orville Wright, with Lieutenant Thomas Selfridge as passenger, crashes killing Selfridge. He becomes the first airplane fatality.

1970    Vietnam War: Lieutenant William Calley goes on trial for the My Lai massacre.

2001    President Bill Clinton posthumously raises Meriwether Lewis' rank from Lieutenant to Captain.