On September 6, 1997, a coffin slowly wheeled through the streets of London on the back of a gun carriage. Within it lay the mortal remains of Diana, Princess of Wales, who had died in a car crash seven days before. The funeral followed strict royal protocol, but what was not planned was the astonishing size of the crowds that flooded the London streets, squares and parks. It was estimated that more than 1 million people turned out to witness the procession. It was one of the largest crowds to appear in England since World War II. Below,

This tradition of massive funeral crowds can be traced back to the Victorian era, and began with the 1852 death of the Duke of Wellington. The vanquisher of Napoleon—and the popularizer of tall, wet-weather boots—stated in his will that his body be left “at the disposal of his Sovereign.” So upon his death Queen Victoria declared that his funeral should be an unprecedented event befitting both the greatness of the Duke’s formidable military career and of the British Empire.

The funeral took two months to prepare, during which Wellington’s body was embalmed and sealed inside four coffins, and a meandering two-mile route through London was plotted. On the day of the funeral 12 black horses with black ostrich feather headdresses pulled an enormous bronze funeral car festooned with spears, helmet crests and cannons, like some immense juggernaut, through the streets of London. Ten thousand marchers followed behind—some of whom were needed to help push the funeral car when it became stuck in the mud—and the watching and weeping audience numbered more than 1.5 million people, many brought there by the new railway lines that now connected the city to the rest of the country. The Illustrated London News declared it “to have surpassed in significant grandeur any similar tribute to greatness ever offered in the world.”

The Duke of Wellington’s funeral, which was covered by the international press, created the blueprint for all massive public funerals to follow. They became events of huge expense, generally organized by the state, and served dual purposes as both events of mourning and demonstrations of national solidarity and unity. Most importantly they were only possible by the increased prevalence of mass transportation.

This last factor was of paramount importance across the Atlantic, upon the death of President Abraham Lincoln in 1865. When Lincoln’s body was carried by train from Washington to Illinois it became a de facto funeral procession, traveling through Pennsylvania, New York, Ohio, Indiana and Illinois on a two-week journey during which time an estimated seven million people stopped to pay their respects. Instead of the people going to the body, the body went to the people.

As well as royalty and politicians, religious figures inevitably draw some of the largest crowds to their funerals. Upon the death of the Ayatollah Khomeini in 1989 it was estimated that nearly ten million people lined the 20-mile route to the cemetery—1/6 of Iran’s population, the largest proportion of a population ever to attend a funeral procession—with between 2.5 to 3.5 million people attending the burial itself. Such demonstrable public devotion can, however, cause difficulties. During the funeral the crowd of mourners swarmed the simple wooden coffin holding the Ayatollah’s body. As thousands of hands tried to grasp a shred of the funeral shroud, the coffin fell to the ground and the body tumbled out. It was eventually reclaimed by armed guards firing shots over the crowd’s heads and was placed on a helicopter to be carried away in order be buried another day. Mourners clung onto the helicopter’s landing gear as it took off.

While lacking such dramatic displays of grief, the funeral of Pope John Paul II was similarly notable for its vast crowd—some 4 million crammed into Rome—that included the largest gathering of heads of state outside the United Nations, with four kings, five queens, and at least 70 presidents and prime ministers paying their respects.

But public or religious service is by no means the only cause of massive public funerals. When the French novelist Victor Hugo died in 1885, more than 2 million people observed the funeral procession from the Arc de Triomphe to the Pantheon, more than the ordinary population of Paris. It was the first celebrity funeral. Although the author of Les Misérables and The Hunchback of Notre-Dame had wished to be buried in a pauper’s coffin, everything around it was magnificent. The Arc de Triomphe where the coffin was placed was veiled in black cloth and surrounded by soldiers on horseback carrying torches. During the procession itself the coffin was preceded by 11 carriages of flowers. It was notable that the majority of the funeral crowd was comprised of laborers and farmers, the very dispossessed that Hugo’s work had championed, and even the prostitutes of Paris took the day off. The Chicago Tribune labeled it, “one of the most remarkable funerals in the world’s history,” although the philosopher Friedrich Nietzsche declared it “an orgy of bad taste and self-admiration.”

Since Hugo’s day, celebrities, especially those who die young, have been the cause of an increasing number of huge funerals. When Ayrton Senna, the Brazilian Formula One racing car driver, died in a crash in 1994, it was considered a national tragedy and the Brazilian government declared three days of national mourning. An estimated 3 million people lined the streets of his hometown of Sao Paulo.

Yet the largest funeral crowd ever recorded was for a man little known outside his home country. Upon his death in 1969, C.N. Annadurai was the Chief Minister of Tamil Nadu, a state in southern India. An actor, writer and proponent of Tamil culture—he fought against the imposition of Hindi as the official language of India—he was universally beloved in his home state. When he died while still in office, it is estimated that 15 million people came out onto the streets to view the body.

While the subject of such a huge outpouring of grief is, perhaps, surprising, that such a crowd should occur in India is less so. After all, India plays host to the Kumbh Mela pilgrimage, which attracts some 30 million pilgrims whenever it is held, the largest gathering of people in the world. Diana’s royalty and celebrity made her a figure of global fame, but in the end her funeral couldn’t hold a candle to that of an Indian state administrator.