Is laughter what truly makes us human? A new comedy series challenges comedians not to laugh at all — and shows us how important laughing really is.
‘Funniest show ever’ hailed by critics
Staying serious: The comedians may be trying to keep a straight face, but Jimmy Carr "cried three times laughing" in the control room. Glossary
Jimmy Carr - A British-Irish comedian, born in 1972.
Amazon - A large river and jungle in South America. Also the name of a US-based company that started off selling books online. It now sells almost any product and is expanding into futuristic computer technology.
Tension - Some point out that the conservation world is dominated by white Western males. That has allowed the powers-that-be to look at it as a racist issue, rather than focusing on protecting wildlife.
Unique - Different to everything else.
Apes - Large primates without tails, such as gorillas and chimpanzees. Humans are apes.
Threatening - Potentially causing danger or harm.
Species - A set of animals or plants with similar features. Members of the same species can breed with each other.