It's a meeting of the world's top two carbon polluters as President Barack Obama and China's leader pull up chairs at the Paris climate conference to discuss efforts to fight global warming.
Both nations already have announced ambitious plans to cap or reduce greenhouse gas emissions in future years.
Now Obama and China's Xi Jinping (shee jihn-peeng) are preparing to meet at the opening of the two-week Paris conference to underscore the need for all nations to come together on a strong agreement to combat climate change.
Obama also is trying to drown out his critics at home. They say his energy plan is unattainable and could be wiped away by his successor.
China emits about 30 percent of the world's greenhouse gases and the U.S. about 16 percent.