On 15 December 2001, the Leaning Tower of Pisa reopened to the public after an unprecedented 11-year closure.

Famous worldwide for its dramatic lean, the tower also became, during the 1990s, the most closely monitored building on Earth. Engineers and scientists watched anxiously as the tilt worsened year by year, raising the very real possibility that the tower could topple.

The lengthy restoration effort — invisible to tourists but watched closely by experts — was a race against time, during which visitors were barred from climbing the tower for over a decade.

The complex €27 million stabilization project reduced the tower’s tilt by around 17 inches, securing the iconic structure for an estimated 200–300 years.

Nunziante Squeglia, professor of geotechnics at the University of Pisa, tells Colm Flynn about the extraordinary moment the tower reopened.

Eye-witness accounts brought to life by archive. Witness History is for those fascinated by and curious about 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 how the Excel spreadsheet was developed, the creation of cartoon rabbit Miffy and how the sound barrier was broken.

We look at the lives of some of the most famous leaders, artists, scientists and personalities in history, including: the moment Reagan and Gorbachev met in Geneva, Haitian singer Emerante de Pradines’ life and Omar Sharif’s legendary movie entrance in Lawrence of Arabia.

You can learn all about fascinating and surprising stories, like the invention of a stent which has saved lives around the world; the birth of the G7; and the meeting of Maldives’ ministers underwater. We cover everything from World War Two and Cold War stories to Black History Month and our journeys into space.

(Photo: The Leaning Tower of Pisa. Credit: Martin Ruegner/via Getty Images)

In the summer of 2003, pharmacist Hon Lik was one of millions of smokers in China.

He was coughing a lot and having problems with his breathing and wondered if he could make an alternative cigarette.

After various experiments, he created a vape prototype. It went on sale in May 2004 and was instantly a hit - selling 100,000 in China.

Hon tells Megan Jones how he brought it to market.

Eye-witness accounts brought to life by archive. Witness History is for those fascinated by and curious about 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 how the Excel spreadsheet was developed, the creation of cartoon rabbit Miffy and how the sound barrier was broken.

We look at the lives of some of the most famous leaders, artists, scientists and personalities in history, including: the moment Reagan and Gorbachev met in Geneva, Haitian singer Emerante de Pradines’ life and Omar Sharif’s legendary movie entrance in Lawrence of Arabia.

You can learn all about fascinating and surprising stories, like the invention of a stent which has saved lives around the world; the birth of the G7; and the meeting of Maldives’ ministers underwater. We cover everything from World War Two and Cold War stories to Black History Month and our journeys into space.

(Photo: Hon Lik smokes his invention. Credit: Frederic J Brown/AFP via Getty Images)

In 1981 one of the world’s most iconic works of art – Guernica - was finally handed to Spain after a 44-year exile.

Pablo Picasso had created the huge mural in 1937 followed the bombing of the Basque town of Guernica during the Spanish civil war.

And, after being shown in Paris, the painting went on tour in Europe and America, where it was loaned to the Museum of Modern Art in New York.

At the time, Picasso swore the painting would never hang in Spain until the country returned to democracy.

It wasn't until after the death of the dictator General Francisco Franco that discussions began to transfer the painting to Spain. Ambassador Rafael Fernandez-Quintanilla was one of the negotiators.

Jane Wilkinson has been through the BBC archives to find out how Rafael helped end the exile. Additional archive from British Pathe.

Eye-witness accounts brought to life by archive. Witness History is for those fascinated by and curious about 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 how the Excel spreadsheet was developed, the creation of cartoon rabbit Miffy and how the sound barrier was broken.

We look at the lives of some of the most famous leaders, artists, scientists and personalities in history, including: the moment Reagan and Gorbachev met in Geneva, Haitian singer Emerante de Pradines’ life and Omar Sharif’s legendary movie entrance in Lawrence of Arabia.

You can learn all about fascinating and surprising stories, like the invention of a stent which has saved lives around the world; the birth of the G7; and the meeting of Maldives’ ministers underwater. We cover everything from World War Two and Cold War stories to Black History Month and our journeys into space.

(Photo: Guernica on display in Madrid, 1981. Credit: Gianni Ferrari/Getty Images)

In 2004, Danish food entrepreneur Claus Meyer launched the ‘Nordic Kitchen Manifesto’, kick-starting a revolution in Nordic cooking focused on local seasonal ingredients.

The new approach was most famously embodied by the Copenhagen restaurant Meyer founded, Noma, which was anointed the world’s best restaurant five times.

New Nordic cuisine is credited with shifting global dining away from the importation of products, and towards its core tenets - freshness, seasonality and localism. Claus Meyer speaks to Ben Henderson.

Eye-witness accounts brought to life by archive. Witness History is for those fascinated by and curious about 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 how the Excel spreadsheet was developed, the creation of cartoon rabbit Miffy and how the sound barrier was broken.

We look at the lives of some of the most famous leaders, artists, scientists and personalities in history, including: the moment Reagan and Gorbachev met in Geneva, Haitian singer Emerante de Pradines’ life and Omar Sharif’s legendary movie entrance in Lawrence of Arabia.

You can learn all about fascinating and surprising stories, like the invention of a stent which has saved lives around the world; the birth of the G7; and the meeting of Maldives’ ministers underwater. We cover everything from World War Two and Cold War stories to Black History Month and our journeys into space.

(Photo: Plates of Nordic cuisine. Credit: Sergei Gapon/AFP)