This weeks sees the World Economic Forum return to the Swiss Alps town of Davos, with observers claiming just two people - one in her teens - will dominate this year’s gathering of the global elite.
With climate change set to dominate proceedings, this Davos is being billed as Trump v Thunberg, and both the US president and the teenage environmental campaigner addressed delegates on Tuesday.
President Donald Trump delivered what organisers called a special address, and hailed his economic record as evidence that his “America First" policy is working.
Here's everything you need to know about it:
What did Greta Thunberg say?
Greta Thunberg kicked off the first day of talks at Davos with a plea to put science at the centre of the conversation on the climate crisis, not her.
Ms Thunberg said the struggle against climate change will require more than just general awareness, adding that science needs to be at the "centre" of the conversation.
Ms Thunberg began proceedings by reflecting on the incredible 18 months since she began her climate strike.
When the 17-year-old was asked if she felt activists are being heard enough, Ms Thunberg said: “I can’t complain about being heard, I’m being heard all the time.
"But science isn’t at the centre of the conversation, and it needs to be," she said.
Stating that "it's not just me", Ms Thunberg acknowledged the hundreds of thousands of young people around the world who have created "an alliance of movements".
"People are more aware now," she said. "It feels like the climate and environment is a hot topic now, thanks to young people pushing."
Despite this, nothing has been achieved as global emissions continue to rise, she said.
"These aren’t anyone’s views, this is the science."
She added that forecasts don't include feedback loops and tipping points and often assume that “future generations will somehow suck hundreds of billions of tonnes of CO2 out of the atmosphere, even though such technology doesn’t exist yet."
"I’ve been repeating these numbers at nearly every speech I’ve given for the last 18 months," she continued.
What did Trump say?
Donald Trump decried climate "prophets of doom" in his keynote speech, calling for a rejection of "predictions of the apocalypse" and saying that America would defend its economy.
Mr Trump did not directly name the teenage climate activist Greta Thunberg, who was in the audience.
Later, she excoriated political leaders, saying the world "in case you hadn't noticed, is currently on fire".
Trump said that it was a time for optimism, not pessimism, in a speech that touted his administration's economic achievements and America's energy boom.
Speaking of climate activists, he said: "These alarmists always demand the same thing - absolute power to dominate, transform and control every aspect of our lives." Greta Thunberg was in the audience.
They were, he said, "the heirs of yesterday's foolish fortune tellers".
What else is to come?
Thunberg will address the forum once again today
Highlights from the 2020 World Economic Forum programme:
For the Forum's full programme, head to the official website
Tuesday 21 January
The Reality of Racial Bias
Public Speakers: Cara Mertes, Phillip Atiba Goff
UpLink: Linking Up the Next Generation of Change-Makers
Public Speakers: Melati Wijsen, Marc Benioff, Punit Renjen, Klaus Schwab, Sarah Kelly, Badr Idrissi, Allen Blue, Fatima Azzahra El Azzouzi
Stakeholder Capitalism: What Is Required from Corporate Leadership?
Public Speakers: Jim Hagemann Snabe, Klaus Schwab, Ginni Rometty, Marc Benioff, Feike Sybesma, Brian T. Moynihan
Wednesday 22 January
Free to Be (LGBTI)
Public Speakers: Ana Mari Cauce, Shamina Singh, Wanuri Kahiu, Tonia Mastrobuoni, Xavier Bettel, Geena Rocero
An Insight, An Idea with Jin Xing
Public Speakers: Lord Tony Hall, Jin Xing
The Power of Youth
Public Speakers: Maxime Crettex, Berengere Fouqueray, Micah White, Naomi Wadler, Autumn Peltier
Securing a Sustainable Future for the Amazon
Public Speakers: Jane Goodall, Mishal Husain, Al Gore, Carlos Afonso Nobre, Ivan Duque
Social Mobility: Reskilling the Next Billion
Public Speakers: Robert E. Moritz, Peter Hummelgaard, Jennifer Morgan, Jim Hagemann Snabe, Maxim Oreshkin, Saadia Zahidi
A History of Feminism in the West
Public Speakers: Brian Schmidt, Mary Beard
What's at Stake: The Arctic
Public Speakers: Sanna Marin, Scott Minerd, Gabriel O'Donnell, Gail Whiteman, Elena Cherney, Al Gore
Gavi at 20: Lessons Learned from the World's Leading Vaccine Alliance
Public Speakers: Klaus Schwab, Sarita Nayyar, Christopher J. Elias, Felix Tshisekedi, Seth F. Berkley, Ngozi Okonjo-Iweala, Paul Hudson
The Future of American Foreign Policy
Public Speakers: David M. Rubenstein, Jane Harman, Gideon Rose, Amos Yadlin
Thursday 23 January
How to Tax the Digital Economy
Public Speakers: Stephen Carroll, Katharina Pistor, Angel Gurría, Bruno Le Maire, Delia Ferreira Rubio
How to Survive the 21st Century
Public Speakers: Yuval Noah Harari, Mark Rutte, Orit Gadiesh
Social Mobility: Getting to 50-50 Gender Parity
Public Speakers: Fareed Zakaria, Sanna Marin, Jonas Prising, Phumzile Mlambo-Ngcuka, Muriel Pénicaud
An Insight, An Idea with Satya Nadella
Public Speakers: Satya Nadella, Klaus Schwab
Closing the Disability Inclusion Gap
Public Speakers: Edward Ndopu, Molly Burke, Caroline Casey
Special Address by Angela Merkel, Chancellor of the Federal Republic of Germany
Public Speakers: Angela Merkel, Klaus Schwab
How to Turn Protest into Progress
Public Speakers: Autumn Peltier, James Harding, Alicia Bárcena Ibarra, Micah White, William F. Browder
Striking a Green 'New Deal'
Public Speakers: Jane Harman, Jesper Brodin, Mark Rutte, Kyriakos Mitsotakis, Frans Timmermans, Penny Abeywardena
How to Measure a New Economy
Public Speakers: Heizo Takenaka, Gillian R. Tett, Douglas L. Peterson, Mariana Mazzucato, Saadia Zahidi
Friday 24 January
A Decade to Deliver the Global Goals
Public Speakers: Mohamad Al Jounde, Paul Stoffels, Sarah Kelly, Achim Steiner, Wanjuhi Njoroge
Being Out and Equal
Public Speakers: Jill Ader, Peter T. Grauer, Geena Rocero
Breaking Free from Single-Use Plastics
Public Speakers: Kristin Hughes, Akira Sakano, Al Gore, Francine Lacqua, Tak Niinami, Melati Wijsen
Global Economic Outlook
Public Speakers: Zhu Min, Steven Mnuchin, Olaf Scholz, Kristalina Georgieva, Haruhiko Kuroda, Christine Lagarde