Historical clue formulations

• Term for groups of [circled letters] — 2026-06-21
• Lookout positions — 2025-06-06
• Broadcasting aids — 2020-06-04
• Air traffic control sites — 2014-09-25
• Minarets, e.g. — 2012-09-01
• TV transmission sites — 2006-10-09
• Rises dramatically — 2002-02-09
• Skyscrapers — 1996-03-21
• New York's Twin _____ — 1994-07-18