In the global battle against the coronavirus, the frontline soldiers are healthcare workers: nurses and doctors armed with dwindling supplies of ventilators and personal protective equipment. The battlefields have been the world’s hospitals – in places like New York City, Madrid, and Wuhan – and the enemy is invisible and ever-present.

In this 30-minute special, Witness to the Pandemic: Acts of Heroism, CNN correspondents take viewers inside the intensive care units and emergency rooms, reporting on the escalating public health crisis and meeting the men and women who perform daily acts of heroism, in an effort to save as many lives as possible. From the whistle-blowers to the volunteers, from tragedy to recovery, this is the story of healthcare in the time of COVID-19. 

CNN’s David Culver, Nectar Gan and Elizabeth Cohen share stories of the medical professionals who are putting their own health on the line to care for others. The risk of going into battle against the coronavirus is becoming infected with the disease yourself – this was highlighted by the story of Dr. Li Wenliang, a whistle-blower who was silenced and eventually succumbed to the virus.

From New York to Madrid, CNN reporters Miguel Marquez, Sara Sidner, Dr. Sanjay Gupta and Scott McLean gain access to the frontlines of the battle against the virus. Here medical equipment is being rationed and in danger of running out, while hard decisions have become the norm.

Whether it’s a German biotech company working on a vaccine or a rapid-test kit developed in three weeks in South Korea, there’s an undeniable sense of urgency in the global fight against the pandemic. CNN’s Ivan Watson and Fred Pleitgen meet the scientists and doctors who are tackling the illness and the pressure couldn’t be higher. 

Witness to the Pandemic: Acts of Heroism premieres Saturday, April 18 at 1am ET, and replays Monday, April 20 at 12pm ET and 10pm ET on CNN International.