The fire in Notre Dame Cathedral in April was the most discussed topic on Twitter.
The second most frequently mentioned hashtag was the beginning of the Rave era, symbolizing the change of emperor in Japan. Venezuela is in third place, where mass protests took place at the beginning of the year, Radio Sputnik reported.
Brexit issues, Typhoon Hagibis, fires in the Amazon, protests in Hong Kong, climate protests, the terrorist attack in New Zealand Christchurch and the pre-election debate of Democrats in the US were also popular.
The most talked about personalities in 2019 were US President Donald Trump, his predecessor Barack Obama, and Indian Prime Minister Narendra Modi.
'Game of Thrones' TV show has also been discussed on Twitter along with 'Avengers: Endgame,' 'The Simpsons' and 'Stranger Things.'
BTS, American singer Ariana Grande and rapper Drake were the most discussed among singers.
By the number of reposts, the photograph of a chicken egg became the most popular.