Tens of thousands of protestors gather on the National Mall for the March for Science in Washington, DC, on April 22. Organizers of the march sought to call attention to climate change, and President Trump's budget cuts to organizations that aid scientific research. The DC march is one of dozens around the US. Hundreds of thousands of people in more than 400 locations across the globe are also taking part in the March for Science to recognise scientific progress, raise awareness of scientific discovery, and defend scientific integrity.  EPA/Jim Lo Scalzo