It is not clear whether staff relax by climbing the institute's walls to the sound of a Liszt concerto before taking a rooftop sauna. If they do, they have Svante Pääbo to thank. "The climbing wall and sauna were my ideas," he says. "When they put together plans for the institute and asked me work here, I insisted they have these. I suppose they fit in with my Swedish identity."

Pääbo is the institute's head of evolutionary genetics and an idiosyncratic researcher, a man obsessed – he admits – with the avoidance of contamination and the need to keep his laboratories and researchers scrupulously clean. In doing so, Pääbo has transformed the study of human origins. Among his achievements, he has sequenced an entire Neanderthal genome, revealing a link between these extinct people and many modern humans. He has also uncovered the existence of a previously unknown human species, called the Denisovans, from DNA extracted from a finger bone found in a cave in Siberia.

"When I started this field 25 years ago I thought we might be able to extract DNA from bones of people born a few thousand years ago and learn something about the ancient Egyptians or about the people who brought agriculture into Europe," says Pääbo. "It was beyond my wildest dreams to think we could resurrect genomes that are hundreds of thousands of years old. To have done that, well, it's really cool."