Twitter has released a list that includes the most influential tweets of 2015. Topping the list are #PrayForParis and #JeSuisCharlie, hashtags that became global rallying cries and expressed solidarity with Parisians after terrorist attacks struck the city two times in one year.

One Direction's Harry Styles holds the record for the single most retweets, with "All the love as always. H," a message sent to fans when news broke that fellow bandmate Zayn Malik was leaving the group.

The message was retweeted 717,982 times.

Meanwhile, the most influential hashtags and subjects that generated the most buzz on Twitter in 2015 are the following :

#BlackLivesMatter: BlackLivesMatter began as a Twitter hashtag and has come to represent a social movement.

#MarriageEquality: People used Twitter this year to celebrate the national legalization of same-sex marriage, notably in the US and in Ireland.

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

#IStandWithAhmed: 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.

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

#FIFAWWC: FIFA Women's World Cup

#PlutoFlyby captured massive attention and the curiosity of Earthlings

#BlueandBlack or #WhiteandGold: One dress, seen two different ways, caused heads to explode.

@Caitlyn_Jenner became the fastest account to reach a million followers.

The full list is available here.