In 1897, three Swedish explorers disappeared while trying to reach the North Pole by balloon. 33 years later, their bodies were found

The North Pole was one of the biggest prizes of 19th-century exploration. Hundreds of people tried to reach it by ship or sledge, but every attempt failed and dozens died. In 1897, Swedish engineer and balloonist Salomon August Andrée decided to attempt what no one had tried before, cross the Arctic by hydrogen balloon.

Andrée set off from Danes Island in Spitsbergen on July 11, 1897, with engineer Knut Frænkel and photographer Nils Strindberg aboard the balloon Örnen, meaning “The Eagle”. The balloon soon became uncontrollable and disappeared into the Arctic. For 33 years, nobody knew what had happened to the three men.

The mystery finally ended in August 1930, when Norwegian explorers found the expedition's remains on Kvitøya in Svalbard. Alongside the bodies were diaries, records, cameras and photographs that had survived in the frozen landscape, allowing the final months of the expedition to be reconstructed.

Andrée believed the North Pole could be reached by balloon

Andrée's interest in ballooning began after he saw aeronautic displays at the Philadelphia World’s Fair in 1876. He later made several balloon crossings of the Baltic Sea and became convinced that air travel could offer a solution to the Arctic exploration problem.

At the Sixth International Geographical Congress in London in 1895, he presented his plan for reaching the North Pole by balloon. He believed steady winds could carry the craft over the pole and toward Alaska.

The Örnen was specially designed for the mission. It was about 20.5 metres in diameter and made from several layers of silk. It carried food and equipment, sledges, boats and tents for the three explorers. Andrée also used long drag ropes and sails in an attempt to control the balloon.

The idea attracted support from Sweden's King Oscar II and Alfred Nobel, but critics argued that the balloon could not be properly controlled.

The balloon lost control almost immediately

When the Örnen launched on July 11, the expedition quickly went wrong. According to Polar Journal, the drag ropes trailing beneath the balloon were pulled into the sea, became tangled and tore away.

The crew had already thrown overboard about 210 kilograms of ballast to gain altitude. Without the ropes and ballast, the balloon rose to more than 700 metres, leaving the explorers unable to steer it effectively.

The Örnen drifted away and was never seen again. It was also the last time anyone saw Andrée, Frænkel and Strindberg alive.

One of Andrée's carrier pigeons was intercepted several days later. A July 13 message said: “82 deg. north latitude ... Good journey eastwards, 10 deg. south. All goes well on board. This is third pigeon post.” No other messages were found.

The diaries revealed why they abandoned the balloon

The recovered records showed that the balloon stayed airborne for nearly three days. Shifting winds pushed it west, while leaking hydrogen and ice forming on its surface made the situation increasingly dangerous.

The balloon eventually began bouncing across the ice, sometimes at intervals of about 50 metres. On July 14, the explorers abandoned it roughly 300 miles from the North Pole.

Strindberg's camera later provided some of the clearest evidence of what happened. Photographs showed the wrecked balloon and the camp the men established near the crash site.

The three then attempted to travel toward Franz Josef Land, hoping to reach emergency supplies. But the drifting ice repeatedly pushed them west instead of east. Their heavy sledges made the journey difficult, while cold, wet conditions and exhaustion slowed their progress.

Their final days remain partly unexplained

By September, the explorers had made little progress. Falling temperatures forced them to prepare for winter, and they built an ice shelter and hunted seals and polar bears.

In early October, shifting ice carried them toward White Island. Andrée made his final diary entry on October 8.

The exact cause of death remains unknown. National Geographic reports that experts believe the men may have had enough supplies to survive the winter but could have been overcome by illness. Other possibilities include exhaustion, hypothermia and injuries.

Popular Mechanics notes that scientists later found parasitic worms in some uneaten polar bear meat, raising the possibility that undercooked meat contributed to severe illness.

The 1930 discovery solved a 33-year mystery

On August 5, 1930, members of the Norwegian seal-hunting vessel Bratvaag landed on Kvitøya during an unusually warm summer. They found the remains of a boat protruding from the ice and an object marked “Andrée's Pol. Exp. 1896”.

Further exploration uncovered the remains of all three men, along with diaries, meteorological records, a camera and film. National Geographic reports that 93 of Strindberg's 240 negatives were recovered and 20 were successfully developed.

The bodies were returned to Stockholm, cremated and buried. The surviving diaries and photographs, however, preserved the story of an expedition that disappeared into the Arctic in 1897 and was not understood until three decades later.