The deepest man-made hole in the world

In the 1970s and 1980s, scientists in Russia managed to dig a hole more than 12,000 metres deep.

It was called the Kola Superdeep Borehole.

They wanted to achieve a world record and learn more about the Earth's crust.

Rachel Naylor speaks to Prof David Smythe, a geophysicist who worked there for four months.

Eye-witness accounts brought to life by archive. Witness History is for those fascinated by the past. We take you to the events that have shaped our world through the eyes of the people who were there. For nine minutes every day, we take you back in time and all over the world, to examine wars, coups, scientific discoveries, cultural moments and much more.

Recent episodes explore everything from football in Brazil, the history of the ‘Indian Titanic’ and the invention of air fryers, to Public Enemy’s Fight The Power, subway art and the political crisis in Georgia. We look at the lives of some of the most famous leaders, artists, scientists and personalities in history, including: visionary architect Antoni Gaudi and the design of the Sagrada Familia; Michael Jordan and his bespoke Nike trainers; Princess Diana at the Taj Mahal; and Görel Hanser, manager of legendary Swedish pop band Abba on the influence they’ve had on the music industry. You can learn all about fascinating and surprising stories, such as the time an Iraqi journalist hurled his shoes at the President of the United States in protest of America’s occupation of Iraq; the creation of the Hollywood commercial that changed advertising forever; and the ascent of the first Aboriginal MP.

(Photo: The site of the Kola Superdeep Borehole in the 1990s. Credit: David Smythe)