In December 1926, Agatha Christie vanished for 11 days, and more than 1,000 police and 15,000 volunteers searched for her. She was found at a Harrogate spa hotel, signed in under the surname of her husband’s mistress

On the night of December 3, 1926, Agatha Christie kissed her sleeping daughter goodnight, left her home in Sunningdale, Berkshire, and drove off into the dark. She didn’t come back.

The next morning, her car was found abandoned near a chalk pit at Newlands Corner, near Guildford in Surrey. It had run off the road into bushes, with its headlights still on. Inside were a fur coat, a suitcase and her driving licence. Christie herself was nowhere to be found.

Next month marks 100 years since one of the strangest real-life mysteries in British history.

A writer on the rise

By 1926, Agatha Christie was already well known. Her detective Hercule Poirot had first appeared in 1920, and that summer she had published The Murder of Roger Ackroyd, a novel whose twist ending caused a sensation.

But her private life was falling apart. Her beloved mother had died earlier that year. And in August, her husband, Archie Christie, a former First World War pilot, told her he had fallen in love with another woman, Nancy Neele, and wanted a divorce.

The biggest manhunt Britain had seen

Christie’s disappearance quickly became front-page news. Police feared she might have come to harm, and the search grew into an enormous operation.

More than 1,000 police officers and an estimated 15,000 volunteers combed the Surrey countryside. For the first time in a British missing-person search, aeroplanes were used. Divers searched local ponds, including the Silent Pool, a spring-fed lake near where her car was found. A newspaper offered a £100 reward.

Even famous writers joined in. Sir Arthur Conan Doyle, creator of Sherlock Holmes, took one of Christie’s gloves to a spiritual medium, hoping it might help find her. Detective novelist Dorothy L. Sayers visited the scene to look for clues.

Suspicion falls on her husband

As days passed with no sign of her, suspicion turned toward Archie. Newspapers reported on the couple’s troubled marriage, and some people wondered whether he had harmed her. Police watched him closely, though no evidence ever pointed to wrongdoing.

Found in Harrogate

On December 14, eleven days after she vanished, the mystery ended in a most unexpected place. Christie was found safe and well at the Swan Hydropathic Hotel, a fashionable spa hotel in Harrogate, Yorkshire, more than 200 miles from home.

She had checked in under the name Teresa Neele, of Cape Town, South Africa, using the surname of her husband’s lover. Staff and guests later said she had seemed relaxed, joining in the hotel’s dances and entertainments. Members of the hotel’s band reportedly recognized her and alerted police, and Archie travelled north to identify her.

What really happened?

The truth has never been fully settled. At the time, Archie said his wife had suffered memory loss, and Christie later said she had no memory of the episode. She left it out of her autobiography entirely.

Some modern writers have suggested she experienced a fugue state, a rare form of memory loss brought on by severe stress or trauma, which can cause people to travel and take on a new identity. Others believe she planned the disappearance, perhaps to embarrass Archie, to spoil his plans with Nancy Neele, or as a cry for help during an extremely painful time. Critics at the time accused her of a publicity stunt, though few historians now think that likely.

What came next

Agatha and Archie divorced in 1928, and he married Nancy Neele soon afterward. In 1930, Christie married archaeologist Max Mallowan, and the marriage lasted for the rest of her life.

She went on to write dozens more novels, plays and short stories, becoming one of the best-selling authors in history. Her books have sold more than two billion copies.

Visiting the places today

Newlands Corner, where her car was found, is now a popular beauty spot in the Surrey Hills with a café and walking trails. The Silent Pool is nearby. The hotel in Harrogate, now called the Old Swan Hotel, still welcomes guests and celebrates its famous link to Christie. It’s long been associated with the Theakston Old Peculier Crime Writing Festival, held in Harrogate each summer.

For a writer whose novels always ended with the mystery solved, it’s fitting that her own greatest puzzle remains open.