Historical clue formulations

• City that's been home to four N.F.L. franchises — 2021-03-19
• City nicknamed "The Gateway to the West" — 2018-07-11
• First U.S. city to host the Olympics — 2018-06-03
• End of the Lewis and Clark Expedition, 9/23/1806 — 2009-04-12
• Super Bowl champs of 2000 — 2004-08-14
• 1904 Olympics site — 2003-08-03
• Bowling Hall of Fame location — 2002-10-02