Fidel Castro's biotech vision

Former President Fidel Castro envisioned Cuba as a "nation of science", investing heavily in a home-grown biotech industry.

Cuba sells drugs all over the world - but not in the US.

Last year, when Presidents Obama and Castro made a momentous move to end hostilities between the two countries, one of Cuba's cancer drugs became the first to be trialled in the US.

Now under President Trump, scientists and patients hope this revolutionary collaboration continues.

Hear more on Assignment from BBC World Service.