This Year on Twitter: 2015's Most Influential Moments

— -- In 2015, the world came together to celebrate marriage equality, support a boy who got into trouble with the law for making a clock, and pray for each other during tragedies, and Twitter became the place to express excitement, grief and solidarity. To commemorate the year, Twitter released on Sunday the most influential hashtags that reached across the globe.

Paris Attacks

Tributes poured in from around the world for Paris as it faced two different terrorist attacks this year. In January, when satirical magazine Charlie Hebdo was attacked and 12 people were killed, Twitter users started tweeting #JeSuisCharlie to show their support. Similarly, as the November attack on the City of Light unfolded, killing 130 people, the world united using #PrayForParis.

Black Lives Matter

The hashtag #BlackLivesMatter became a unifying message for communities after multiple police shootings of African Americans in several U.S. cities. According to Twitter, the hashtag was tweeted 9 million times throughout the year and has come to represent a social movement.

Marriage Equality

Two hashtags became hugely popular as users celebrated marriage equality: #HomeToVote and #LoveWins. Irish citizen expats used the “Home to Vote” hashtag as they returned home to vote in the gay marriage referendum in May and users across the U.S. tweeted “Love Wins” to celebrate the Supreme Court’s legalization of gay marriage in June.

Refugees Welcome

The hashtag #RefugeesWelcome became a top tending topic as users called on European countries to grant entrance to the thousands of refugees from the Middle East and Africa. Human rights activists and people across the world used the platform to show support to the refugees seeking asylum in Europe.

National Elections

Voters took to Twitter to take part in political conversations surrounding elections around the world, including Argentina, Canada, Singapore, India and the U.K.

I Stand With Ahmed

A Texas teen named Ahmed Mohamed and his clock became the focus of worldwide attention after Mohamed was arrested for bringing a homemade digital clock to school because school officials feared it was a bomb. #IStandWithAhmed sparked a worldwide conversation, with more than 370,000 tweets, according to Twitter. Users expressed support for the teen, who received an invitation to the White House from President Obama himself and who received encouragement from Facebook CEO Mark Zuckerberg, the Massachusetts Institute of Technology and Google.

FIFA Women’s World Cup

For those who couldn’t attend the FIFA Women’s World Cup that took place in Canada this summer, Twitter became a place to celebrate victories, share commentary and create a worldwide conversation. Tweets about the topic were viewed 9 billion times from June 6 to July 5, according to Twitter.

Pluto Flyby

The New Horizons spacecraft coming within 7,750 miles of Pluto’s surface sparked curiosity around the world, generating more than 1 million tweets on July 14, according to Twitter.

The Dress Debate

In one of the most heated debates of the year, people used hashtags “BlueandBlack” and “WhiteandGold” to discuss the color of the dress that generated 4.4 million tweets in just two days. No matter the color, the optical illusion became an Internet sensation, sparking debate across the globe and was even dubbed "DressGate."

Caitlyn Jenner

Caitlyn Jenner received a warm welcome from Twitter users when she first created her account in June. In just over four hours, she gained 1 million followers, which broke the record set by President Obama and claimed the record as the fastest time to reach that many followers.