A number of world leaders have delivered their annual new year messages.
As the world ushers in 2019, a number of high-profile world leaders have reflected on the year gone by and what they hope to achieve in the 12 months to come.
President Xi Jinping said China will continue to open its doors to the world in 2019 but will do so with its sovereignty in mind.
It comes amid a slowing economy, a potential trade war with the United States, and as China looks to strengthen its standing in the South China Sea and the Indo-Pacific region.
"As we open our eyes to look at the world, we are faced with huge changes, changes not seen in 100 years,” Mr Xi said in an address carried by all major state media.
“No matter how the international situation changes, China's confidence and determination to safeguard national sovereignty and security will not change.
“China's sincerity and goodwill for maintaining world peace and promoting common development will not change."
Donald Trump used his medium of choice, Twitter, to deliver a short and very 'Trumpesque' message where he told the country it was going to be "a great year".
"While I'm at the White House working, you're out there partying tonight - but I don't blame you," Mr Trump said.
"Enjoy yourselves, we're going to have a great year. Have a really, really happy new year."
Unlike other leaders that used their messages to outline their country's vision, Mr Trump spent day one of 2019 busy tweeting his thoughts and policy agenda on the Mexican wall, Elizabeth Warren declaring her 2020 presidential run and North American Free Trade Agreement (NAFTA).
He also defended his recent decision to withdraw US troops from Syria.
Chancellor Angela Merkel pledged to get her country more involved on the international stage.
Complex global problems such as climate change, migration and terrorism cannot be solved alone, she said.
"We build on what our predecessors have left us and shape the present for those who come after us,” Ms Merkel said.
“My guiding belief is that we will only master the challenges of our time if we stick together and collaborate with others across borders."
Ms Merkel, who has given up leadership of her Christian Democratic Union party and will step down as Chancellor in 2021, also pledged to increase spending on defence and aid.
Ms Merkel has been a leading defender of multilateralism, an alliance of multiple countries pursuing a common goal, unlike a growing number of other countries in Europe and the United States.
She narrowly averted the near collapse of her coalition government in 2018, which started over dissatisfaction with Germany welcoming over a million migrants in 2015.
Prime Minister Theresa May said the UK “achieved a lot” in 2018.
She urged politicians to back her embattled Brexit deal, two weeks before a vote in parliament and under four months before the scheduled exit from the European Union.
Ms May postponed the vote on her Brexit in December to avoid defeat, sparking a vote of no-confidence against her, which she survived.
Allowing her Brexit deal to go through will allow the government to focus on solving domestic problems, Ms May said.
“The employment rate is at a record high. Our debt is starting its first sustained fall in a generation. And the number of people in absolute poverty is at a record low,” she said.
“If we come together in 2019, I know we can make a success of what lies ahead and build a country that truly works for every one of us."
President Emmanuel Macron said he has three wishes for 2019: "truth, dignity, and hope".
He used part of his speech to urge national unity, as well as criticise elements of recent anti-government protests.
At least six people have died and some 1,400 have been injured since protests over fuel tax rises erupted in December.
They are expected to continue into 2019, despite Mr Macron backtracking on planned fuel tax hikes and signalling wage rises for poorer workers.
Mr Macron said while he understands people are upset, some protesters seeking to speak "in the name of the people" are undermining his government.
“Some take as a pretext that they speak in the name of the people - but what people? Where? How?,” he said.
“In reality, they are nothing but a megaphone for a crowd full of hatred who rail against elected representatives, forces of order, journalists, Jews, foreigners and homosexuals.”
“That, quite simply, is the negation of France."
President Vladimir Putin also called for national unity, amid ongoing tensions with western countries and sanctions by the West against Moscow.
Mr Putin emphasised the need to rely on internal resources to improve living standards, and for citizens to act as "a strong, united team."
"We know for certain that we can achieve the best for ourselves, for our families, for the home country, only with our own efforts and well-organised collaboration,” he said in a televised speech just before midnight.
2018 saw Russia's world image soften a little after hosting the FIFA World Cup - but there was anger domestically, over a proposal to raise the pension age five years to 65 for men, and eight years to 63 for women, to help cope with a shrinking workforce.
UN Secretary General Antonio Guterres said issues relating to climate change and political division are getting harder to solve and international collaboration remains the best hope to combat them.
He pointed to Yemen as an example, where recent breakthrough talks “have created an opportunity for peace”, and an agreement between warring factions South Sudan.
"When international cooperation works, the world wins,” Mr Guterres said in a video released by the UN.
“In 2019, the United Nations will continue to bring people together to build bridges and create space for solutions.
“We will keep up the pressure and we will never give up.”