On July 14, 2017, the remains of a Swiss couple were discovered in the Swiss Alps after 75 years buried underneath a glacier. During a routine maintenance inspection, a ski-lift technician came across the couple’s “perfectly preserved” bodies on the Tsanfleuron glacier near the Swiss city of Berne, where Marcelin and Francine Dumoulin lived. The bodies were dressed in well-preserved World War II era clothing and had with them backpacks, watches, mess kits and a glass bottle, according to the Valais police.

The Dumoulins went missing on August 15, 1942, at ages 40 and 37 years old, on their way to a mountain pasture to feed their cattle. Rescue teams and local villagers searched for the couple after they vanished but came up with no clues as to the couple’s whereabouts. The Dumoulin’s disappearance left seven children– five boys and two girls– orphans. The children were split up and sent to live with different families in the neighborhood, but they would reunite each year on the anniversary of their parent’s disappearance and climb the glaciers to pray, according to the New York Times.

Following the discovery of the two bodies in July, the couple’s remaining living children, grandchildren and great-grandchildren attended a funeral service held in Saviese, Switzerland. Marceline Udry-Dumoulin, 79, the youngest of the Dumoulin’s seven children, told reporters that she wore white to her parents funeral on July 22 because “white represents the color of hope, which she never lost.” Another daughter, Marceline, told local paper Le Nouvelliste that “joy, acknowledgment, serenity, peace” are what she feels at her parent’s funeral.

It is now assumed that the couple fell into a crevasse in the Tsanfleuron glacier, which lies about 2,600 meters above sea level, and their bodies had been trapped there ever since. The Dumoulins were among 280 people listed as missing in the Alps and nearby regions since 1925. It was not until the Tsanfleuron glacial ice began to melt that the bodies became visible.

When asked about the danger of glaciers, Martin Beniston, a climate scientist from the University of Geneva, told GlacierHub, “Glaciers are rather hazardous surfaces and unwary. Skiers or trekkers often get injured or killed when falling in crevasses or if a snow-bridge that covers a crevasse collapses under the weight of the person.”

Nadine Salzmann, a Swiss geographer at the University of Fribourg, Switzerland, added, “In earlier days, people had to cross glaciers when moving from one mountain valley to the next for trading goods, etc. Mountaineers need to be even more careful when moving on glaciers, as glaciers have been changing their ‘face’ very quickly for the past decades.”

How were the Dumoulin’s bodies preserved after so many years? Human tissue has a high-water content, so when put under frozen conditions, the ice crystals in the tissue can sublimate, according to an interview in Live Science with Dan Fisher, a professor at the University of Michigan.

Sublimation is a change in a state of matter where a substance transforms from solid ice to water vapor without passing through a liquid phase; therefore, the tissue dries out. The cold and dry conditions of the Tsanfleuron glacier stopped the bacteria and fungi from breaking down the tissue, keeping both bodies intact.

The Dumoulin story is similar to other discoveries made as glaciers around the world shrink due to climate change. For example, in 2003, coins, leather, arrows, and piece of a wooden bowl, all dating back to 4500 B.C., were discovered at the Schnidejoch glacier, about 20 miles away from Tsanfleuron.

Since 1900, the Alps have lost about half of their volume, and global warming has caused the Tsanfleuron glacier to lose up to half a meter a year. Many long-buried bodies and objects from decades past are now surfacing across the world, as rising temperatures cause more glaciers and ice to melt.

These new discoveries can create opportunities to study past cultures, but preservation can be complex. Once the icy bodies are taken out of their glacial dwelling, they are prone to rapid decay and can disappear from exposure to the elements. In fact, the change in humidity has been turning discovered mummies into black ooze.

Scientists can attempt to save the mummies by hindering the degradation process in a museum-controlled environment by adjusting the humidity, temperature and light in a room. The difficulty remains in protecting the bodies that are in sites exposed to the natural environment.