Nike Air Max Day is Sunday. Here's how the huge sneaker holiday, known for hyped drops, got its start.

• Nike Air Max Day is one of the highly anticipated days on the sneaker calendar.
• It launched in 2014, and Nike has released sneakers from its Air Max vault to mark the occasion every year.
• Sneakerheads celebrate the day by wearing their favorite Air Max sneakers and posting photos online.

Nike Air Max Day, one of the highly anticipated days on the sneaker calendar, is on Sunday. 

The event celebrates all things Air Max, a Nike sneaker franchise that dates back nearly four decades.