What is ‘404 Day’ and why are Atlantans talking about it?

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This story has been updated.

If you've been on Twitter today, you may have noticed Atlanta sports teams and residents posting about #404Day, showcasing their love and pride for the city.

And Atlantans—including Mayor Keisha Lance Bottoms and Killer Mike—are loving it.

Bottoms even promoted a special app just for Atlien emojis!

But with a little Twitter scrolling, you might also notice some love for the Roland SP-404 Sampler, considered one of the world’s most popular portable samplers and a favorite among live-sound engineers and DJs.

It’s a little confusing.

We'll go ahead and let that one slide, but according to 404day.com, April 4 marks "Atlanta's own holiday" (an appropriate hat tip to Atlanta's popular 404 area code) and highlights the city's music, arts, food and spirits scene.

The holiday started on April 4, 2012, at Atlanta staple Clermont Lounge, where musicians and dancers performed for the attendees.

Over the years, popular Edgewood venues such as the Music Room and Noni’s hosted block parties, dance competitions and featured art displays and live installations from local artists.

In the past, the 404 Day events have attracted more than 2,000 attendees, according to 404day.com.

This year, an 18-and-up party featuring more than 25 of Atlanta's top artists and DJs will be held at Smith's Old Bar. Doors open at 9 p.m. for general admission and at 7 p.m. for VIP ticketholders. Tickets range between $12-$40. You can purchase 'em here.

And if you’re just looking to share some Atlanta love, tweet out your favorite photos of the skyline and love letters to the city using the hashtag #404Day.