Just before this BBC podcast gets underway, here's something you may not know.

My name's Linda Davies and I Commission Podcasts for BBC Sounds.

As you'd expect, at the BBC we make podcasts of the very highest quality featuring the most knowledgeable

experts and genuinely engaging voices. What you may not know is that the BBC

makes podcasts about all kinds of things like pop stars,

poltergeist, cricket, and conspiracy theories and that's just a few examples.

If you'd like to discover something a little bit unexpected, find your next podcast over at BBC Sounds.

This is the BBC.

Hello, this is the shorter World Service edition of More or Less.

This week, the great Hans Rosling displays Ruth Alexander's ignorance.

Hello and welcome to more or less on the BBC World Service. I'm Ruth

Alexander. Earlier this year one of more or less his favorite people died, Professor Hans Rosling, of the Gapminder

organization in Sweden. Hans was one of our heroes because he was kind of an international development myth buster with a mission to defeat ignorance about life on earth.

Go to YouTube and watch his videos.

Honestly, they'll change the way you look at your world.

This week, as a tribute to Hans,

we're re-running my interview with him

from a couple of years ago.

He asked me three questions from his ignorance test.

See if you can do better than I did.

The first one is about vaccines of children. The most important vaccine is the well-established

measles vaccines, which is enormously important, especially for poor children that are malnourished,

...