Holidays September 17, 2024 4:23 pm What is Constitution Day? Constitution day is a federal holiday that commemorates the signing of the U.S. Constitution in 1787. US & World Videos 1:38 2 comets from the Oort Cloud can be seen in October 2:06 What's the difference between El Niño and La Niña? 2:35 Prada, Axiom Space unveil new spacesuit for Artemis 3 mission 4:09 Tyra Banks closes Victoria Secret's Fashion Show & more iconic moments 2:27 Child porn investigation reveals former San Jose school employee paid students for content, court documents show