Incredible things happen on Twitter each day.
Here are the moments that had the biggest impact across the world.

 

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#PrayForParis and #JeSuisCharlie became global cries for solidarity after terrorist attacks in Paris.

As the horrific attacks in Paris unfolded in November, the world united on Twitter to report and support people in the City of Light. The hashtag #PrayForParis quickly emerged as a top global trend, while #PortOuverte, a hashtag designed to help people in Paris looking for shelter, also became popular.

The events of November 13 came about 10 months after terrorists attacked the Paris offices of satirical magazine Charlie Hebdo. After that incident, citizens rallied around the phrase “Je Suis Charlie” to show their support and sorrow for the victims. And the entire world joined in on Twitter using the hashtag #JeSuisCharlie, which quickly became a global cry for freedom of expression and solidarity.

 

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#BlackLivesMatter emerged as one of the most powerful social movements in 2015.

#BlackLivesMatter began as a Twitter hashtag and has come to represent a social movement. The hashtag or phrase was Tweeted 9 million times in 2015.

It now serves as a unifying message for communities discussing events around #Ferguson, #Charleston, the #BaltimoreProtests, and individual incidents involving police and Black citizens.

 

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#HomeToVote and #LoveWins signified international support for and celebration of marriage equality.

People used Twitter this year to celebrate the national legalization of same-sex marriage, notably in the US and in Ireland. The #HomeToVote hashtag became hugely popular when Irish citizen expats shared their experience returning home to vote in the gay marriage referendum on May 21.

The #LoveWins hashtag and Twitter emoji celebrated the Supreme Court’s decision to legalize gay marriage in the US on June 26.

 

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#RefugeesWelcome became a top trending hashtag for people from the Middle East seeking refuge in Europe.

As many thousands of refugees from the Middle East and Africa have sought asylum in Europe, human rights activists and other citizens have chimed with the hashtag #RefugeesWelcome.

People around the world have used the hashtag to call on European countries to grant the refugees entrance.

 

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As the world learned about a 14-year-old detained at his school in Texas, #IStandWithAhmed sparked a significant conversation on profiling and discrimination.

When 14-year-old Ahmed Mohammed was detained and handcuffed at his Texas school for bringing in his homemade digital clock (the ostensible fear: it was a bomb), a photo of the high school freshman in handcuffs went viral on Twitter.   

In less than six hours, the hashtag #IStandWithAhmed emerged to support him, and sparked a global conversation with more than 370,000 Tweets. Supportive responses from public figures included President Obama.

 

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National elections in Argentina, Canada, Singapore, India, and the UK dominated the civic conversation.

Twitter is a place for voters to partake in public discourse, and this year, discussion around major elections rocked Twitter.   

As citizens converged on voting booths and ballot boxes in Argentina, Canada, Singapore, India and the UK, civic conversations took place on Twitter.

 

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Fans around the world cheered on the best women in soccer during the #FIFAWWC.

Football (a.k.a. soccer) fans who couldn’t attend the FIFA Women’s World Cup in Canada this summer followed the action on Twitter, creating a massive global conversation.

Whether it was a celebratory “gooooaaalll!” Tweet or commentary on a save or penalty kick, Tweets about the #FIFAWWC were viewed 9 billion times from June 6 to July 5, making the tournament one of the largest global sporting events of the year.

 

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The #PlutoFlyby captured massive attention and curiosity of Earthlings.

Twitter did not exist when @NasaNewHorizons left Earth in 2006, but it is where the whole world came to discuss the historic #PlutoFlyby.

Buzz around the spacecraft coming within 7,750 miles of Pluto’s surface, and the close-up images captured, generated more than 1 million Tweets on July 14.

 


  
One dress, seen two different ways, caused heads to explode.

A photo of the same dress seen in different light suddenly went viral on Twitter and captured the attention of millions of people who marveled at the optical illusion or delved into the science behind the apparent change of colors.

As people debated #BlueandBlack or #WhiteandGold, the dress sparked a global conversation, with more than 4.4M Tweets on February 26 and 27.

 

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Caitlyn Jenner’s new Twitter account became the fastest to reach a million followers.

In June, the world met @Caitlyn_Jenner via Twitter. In just over four hours, she amassed over 1M followers (breaking the record set by @POTUS).

By claiming the record as the fastest time to reach that mark, she also gained recognition in the Guinness World Records.

 


These moments were selected based on level of influence they had on Twitter in 2015. Various factors were considered, including volume of conversation, global resonance and impact.