Tributes are being paid to Mikhail Gorbachev, who's died at the age of 91 following a long illness.
The former Soviet leader is credited for ending the Cold War without bloodshed.
He won the Nobel Peace Prize in the 90s for his efforts to reduce nuclear arms, but his reforms led to the collapse of the Soviet Union.
Taoiseach Micheál Martin says Gorbachev "truly changed the world" and was "one of the most significant political figures of the late twentieth century".
United Nations secretary-general Antonio Guterres, described him as a 'towering global leader'.
The US President says Mikhail Gorbachev was a "remarkable man of vision" who dramatically reduced the potential for a third World War.
Arnold Schwarzenegger called him one of his 'heroes' and says he was 'unbelievably lucky' to call him a friend.
In a social media post, the actor and former governor of California said Gorbachev will be 'remembered for all time as a hero'.