Max Pearson presents a collection of the week’s Witness History episodes.

We hear two stories from the deadly 2004 Boxing Day tsunami, which killed thousands of people in south-east Asia.

Our expert guest is Ani Naqvi, a former journalist who was on holiday in Sri Lanka when the wave hit.

We also hear from the two Polish students who created the voice of Alexa, the smart speaker.

Plus, the story of Klaus Fuchs, the German-born physicist who passed nuclear secrets to the Soviet Union while working on the first atomic bomb.

Finally, we find out about Robert Ripley, the American cartoonist who made millions from sharing bizarre facts.

Contributors:

Choodamani and Karibeeran Paramesvaran – couple whose three children died in the Boxing Day tsunami.

Dendy Montgomery – photographer who captured the tsunami devastation.

Ani Naqvi – former journalist who was caught up in the tsunami.

Lukasz Osowski and Michal Kaszczuk – creators of Alexa.

Klaus Fuchs-Kittowski – nephew of atomic spy Klaus Fuchs.

John Corcoran – director of exhibits at Ripley’s.

(Photo: Tsunami devastation in Indonesia. Credit: Getty Images)