Thousands of protesters fill Tom McCall Waterfront Park during the March for Science in Portland, Oregon, on Saturday, April 22. Protests were held in cities around the world against President Donald Trump's policies. Alex Milan Tracy/SIPPL Sipa/AP

Thousands participate in the National March for Science in Rome, Italy, on Earth Day. Jacopo Landi/SIPPL Sipa/AP

A woman wears a brain beanie during the March for Science in Portland. Alex Milan Tracy/SIPPL Sipa/AP

People show support of scientific research in Berlin, Germany, residents march behind a sign that reads, "There are no alternatives to facts." Sean Gallup/Getty Images

Scientists and science enthusiasts march in London. Natasha Quarmby/REX/Shutterstock/AP

Marchers gathered in front of the Brandenburg Gate in Berlin. Similar marches drew people in more than 500 cities around the world. Sean Gallup/Getty Images

Marchers at the Paris March for Science holding signs. In addition to Paris and Berlin, marches were schedued in Rio, Munich, San Francisco, Boston, Oklahoma City and Bratislava, Slovakia. FRANCOIS GUILLOT/AFP/Getty Images

Scientists at the Neumayer Station in Antarctica take part in the March for Science on April, 22. Alfred-Wegener-Institut/Nadine Michel

Marching in support of scientific research in Berlin, Germany. Many of the marches featured music and speeches. Sean Gallup/Getty Images

A woman in Vienna, Austria,attends the March for Science there. In the US, many marchers have been galvanized by President Donald Trump's proposed cuts to scientific research, including slashing $5.8 billion from the budget of the National Institutes of Health. HANS PUNZ/AFP/Getty Images

Researchers and scientist protest against budget cuts during the March for Science in Madrid, Spain. Marcos del Mazo/LightRocket/Getty Images

People stand together in Martin Place, in Sydney, Australia,for the city's international March for Science. DAVID MOIR/EPA/REX/Shutterstock/Rex Features/DAVID MOIR/EPA/REX/Shutterstock

Scientists and science enthusiasts gather prior to the start of the March for Science in central London. DANIEL LEAL-OLIVAS/AFP/Getty Images