Get out your phones and turn that camera back around. It's National Selfie Day — not that Americans need any special reason to take pictures of themselves. 

June 21 celebrates the popular self-portrait photographs, better known as "selfies," that have become an inescapable trend over the past few years. Selfies are nothing new, of course — people have been taking pictures of themselves since the earliest days of the camera — but the advent of the camera phone has made the technique a phenomenon. Now Americans can't turn around at a popular tourist spot, sporting event, or party without seeing somebody snapping a couple pictures of themselves. 

There are a lot of selfies out there these days, but here are the 8 most famous in honor of National Selfie Day:

1. The Oscars Selfie

The selfie heard round the world... well, retweeted around the world. While hosting the 2014 Oscars, comedian Ellen DeGeneres set out to post the most-shared photo in the history of social media, and she delivered. DeGeneres walked through the star-studded audience and recruited some of Hollywood's biggest names for a one-of-a-kind group selfie. The celebrity-filled photo included Meryl Streep, Bradley Cooper, Lupita Nyong'o, Julia Roberts, Brad Pitt and Jennifer Lawrence, among others. The classic moment has been imitated quite a few times, but never replicated. And the over 3 million retweets is still mighty impressive. 

2. The Space Selfie

If the key to a successful selfie is a great backdrop, then no one can beat International Space Station astronaut Aki Hoshide. Hoshide snapped a photo of himself floating around in outer space, space suit and all, in 2013. As an added bonus, Hoshide framed the reflection of the Earth from outer space in the mask of his helmet front and center in the out-of-this-world selfie. Now that's really cool.

3. The POTUS Selfie

When the president of the United States is taking selfies, you know it's a thing. When Barack Obama joined Instagram in 2014, he christened his new social media account with a selfie of him and his right-hand man, Vice President Joe Biden, riding around in a motorcade. The pair's picture takes the prize for the most presidential selfie — the seal of the President of the United States is even visible on the car seat between them. 

4. The First Selfie

While cell phone cameras might be the weapon of choice for selfie takers these days, the first selfie dates all the way back to 1839, when American photography pioneer Robert Cornelius snapped this sly shot of himself by running into the frame while his camera was getting the shot — in Cornelius' day a photograph took so long to make (exposure-wise) that Cornelius was able to start the process, run into the frame, and then get back to the camera to replace the lens cap. 

Robert Cornelius The first selfie ever taken — in 1839. Photo: Library of Congress

5. The Kim K Selfie

Kim Kardashian has broken the internet on multiple occasions with NSFW photos of her very famous, very scrutinized body. Just a few months ago in March she posted a picture of herself nude, with blonde hair, standing in front of a mirror, casually wondering what to wear. However, the most iconic selfie Kardashian has posted to date was when she showed off her nude, pregnant body in August 2015 shortly before the birth of her second child with husband Kanye West. The photo was empowering proof that pregnancy, self-confidence and sex appeal can all coexist. 

6. The 'Hijack Selfie'

2016's most iconic selfie is also perhaps the most unexpected selfie of all time. When Seif Eldin Mustafa hijacked an EgyptAir flight in March in an attempt to reach his ex-wife in Cyprus, one passenger seized the opportunity for a legendary photo. 26-year old Ben Innes snapped a picture of himself beside the hijacker, who claimed to be wearing a suicide vest. After the frightening situation was resolved peacefully, Innes' photo became the subject of controversy as many criticized the move as irresponsible and reckless. While Innes' photo is not technically a selfie — a flight attendant took the photo — the picture became widely known as the "Hijack Selfie."

7. The T-Swizzle Selfie

With fame comes intense scrutiny. Pop mega-star Taylor Swift's appearance and personal life are the subject of endless tabloid gossip. That's why Swift's 2015 selfie of her in bed, sans makeup, hanging out with her cat is so special. The singer looked stunning without the aid of a team of stylists and reminded the world that she was still just one of us. 

8. The Endorsement Selfie

Kim Kardashian makes another appearance here with her selfie this past January endorsing Democratic presidential candidate Hillary Clinton. That a selfie would be the platform for a presidential endorsement, even from a celebrity, is significant. That the selfie in question includes Clinton, Kardashian and rapper Kanye West makes it iconic.