It was a crisp Saturday in September 1979, and a breeze was blowing strong and steady from the north.
That's what would help Günter Wetzel and his colleague Peter Strelzyk escape East Germany with their families in the middle of the night -- thanks to a hot air balloon they'd built from scratch using only a magazine article as a guide.
"The thought of leaving had been festering in my mind for years, but it was clear that it was very, very dangerous to go via a land route," said Wetzel, now 65 years old. "When I saw pictures of these balloons, I knew it was a possibility."
Wetzel talked to CNET through a German interpreter shortly after the 40th anniversary of his flight and ahead of the 30th anniversary of the fall of the Berlin Wall on Nov. 9. The flight was one of the most daring and ingenious escapes ever made from East Germany. There was no certainty of success, and failure would have meant imprisonment or even death. For Wetzel and many others, the desire for freedom outweighed the risks.
"If we hadn't been so optimistic, we probably couldn't have done it," he said.
Wetzel and Strelzyk have told different accounts of their escape, with each man claiming credit for the idea. They stopped talking shortly after arriving in the West and never reconciled before Strelzyk's death in March 2017. What follows is Wetzel's account of their flight to West Germany.
A divided Germany
After World War II, Germany was divided between East and West. The West, with the help of the US and Britain, flourished and modernized. The East, under the influence of the Soviet Union, struggled. About 3.6 million East Germans, 20% of the population, fled between 1945 and 1961.
East Germany, known as the German Democratic Republic (GDR) or Deutsche Demokratische Republik (DDR), didn't want the rest of its citizens to leave for the richer West, so in August 1961 it built barriers to keep its people in. The official GDR line: It wanted to keep "decadent, immoral westerners out."
The Berlin Wall's 96-mile-long, 12-foot-tall concrete barrier is well known, but simple barbed wire fences divided other parts of the country. Trying to climb over the barriers would set off machine guns, mines and other horrors. Soldiers patrolled a no-man's land along the border.
About 150,000 people attempted escape during the 28 years that the East German barrier existed. An estimated 40,000 succeeded. While some East Germans flew planes to safety, no one had ever attempted escape by balloon.
Life in East Germany
Life in Westzel's home of Pössneck, which today has a population of about 12,000 people, was typical for most of East Germany. The Czech Republic is about an hour's drive east, and it's bordered on the west by Bavaria, part of West Germany.
The Socialist Unity Party of Germany (also known as the East German Communist Party) held tight control over peoples' lives, professions and futures. Opposing political views were squashed, and the dictatorship prevented free elections and freedom of movement. The Ministry for State Security, commonly called the Stasi, forced neighbors to spy on each other and compiled extensive files on citizens. Food, supplies and housing shortages were part of daily life.
Wetzel lived in a single-family home that he renovated in his spare time. He drove a truck delivering furniture and construction materials. In the eyes of the government, Wetzel had black marks against him: His father had fled to the West, and Wetzel had refused to join the Communist Party. Because of that, the GDR denied Wetzel's request to study physics after high school. Instead, he studied forestry, bricklaying and truck driving.
His love of physics is partly what drove Wetzel's desire to leave East Germany -- and a big reason why he succeeded with the seemingly outlandish idea for a hot air balloon.
"The private part of life in the GDR, my family and I enjoyed," Wetzel said. "It more was the public life. We couldn't express our opinions."
While Wetzel couldn't work in or study the sciences, he tinkered with machines in his spare time. He built electric and lighting systems for his home and repaired the building's plumbing.
In 1974, he met Peter Strelzyk through family members visiting from the West (which was permitted at the time). The two men later worked together as self-employed electricians.
In March 1978, Wetzel's sister-in-law, who had left East Germany in 1958, returned for a visit and brought a magazine with an article about the International Balloon Fiesta in Albuquerque, New Mexico. When he saw photos of hot air balloons floating in the air, he thought, "This can't be that difficult." He immediately told Strelzyk about the idea, and they decided that a hot air balloon would be the way to leave East Germany with their wives and children.
"We didn't think it was a crazy plan at all," Wetzel said. "We were totally sure we'd finally found a secure plan to leave the GDR."
The science behind the balloon
Hot air balloons are relatively simple. Heat air inside a balloon using a burner, and it will rise. Attach a basket to the bottom to hold the burner and passengers, and the balloon will float where the wind takes it.
But making a hot air balloon that could carry eight people to West Germany wasn't easy.
For Wetzel and Strelzyk, building a balloon was a matter of trial and error. "I looked at the pictures and kind of estimated how big the balloon was and how big the people in the picture were," Wetzel said. He made mental calculations, ultimately settling on 1,800 cubic meters (63,566 cubic feet).
The two men bought reams of material, largely fabric used to line leather because it was available in large quantities. They initially stored the fabric in Wetzel's house, cutting and sewing in his bedroom on the second floor. As they progressed, the balloon became too heavy to carry upstairs so they moved to the basement of Strelzyk's home.
The men needed a propane gas fire burner to power the balloon. They took a section of stove pipe about 12 centimeters in diameter, connected it to a gas cylinder and added a hose, valve and nozzles.
Next came a basket. They couldn't weave a fancy basket but instead welded together a 1.4-square-meter (15-square-foot) steel frame.
On April 28, 1978, they were ready for a test flight. They traveled to a forest clearing near Ziegenrück and had their wives hold open the balloon. Wetzel and Strelzyk used the burner to warm the air, but nothing happened.
Wetzel and Strelyzk had miscalculated -- badly. The fabric they used was too porous, letting hot air escape. Air-proofing chemicals would make the balloon too heavy. They had to give up.
"The balloon wouldn't even take off of the ground," Wetzel said. They burned it to destroy all traces of their plot. But that only made them more determined to build one that could fly.
"Our sole focus became to create a balloon that would bring us over to the West," Wetzel said.
With the second attempt, Wetzel and Strelzyk were more methodical. Their experience had taught them about gases, as well as how big the balloon actually needed to be. Their first balloon wouldn't have been nearly big enough for eight people. And then there was the fabric. They knew what they'd used before didn't work but had no idea what would be best.
So Wetzel created special tools, including a U-shaped glass tube to test air pressure and the porousness of the materials. That helped them narrow down the choice of materials.
The men ended up using 900 square meters of taffeta -- fabric used in ball gowns -- which they bought in a store in Leipzig at the beginning of June. They told the shopkeeper they were buying fabric to make sails for a boating club.
They also had to adjust the size of the balloon. Wetzel referred to a couple of physics books he kept at home to determine engineering thermodynamics and the effects of temperature changes on the behavior of air. That helped him calculate what he thought was the right dimension for the balloon: 2,200 cubic meters, up from 1,800 before.
They also fashioned a blower out of the engine from Wetzel's motorcycle, letting it fill the balloon with cool air before it was heated. That turned out to be key. Within minutes of starting the blower and turning on the burner, the balloon was fully inflated. But the burners went through gas too quickly, allowing the air to cool. The burner's performance continually worsened, so much so the balloon barely stayed inflated.
They started experimenting, adding cylinders and changing the composition of the chemicals until ending up with a combination of gasoline and oxygen.
"One can imagine how this combination of fuel and oxygen would have behaved and what terrible things could occur," Wetzel noted on his website. "Fortunately, nothing dramatic happened and the flame reached a height equivalent to a three [story] house."
It was during the building of the second balloon that a rift emerged between Wetzel and Strelzyk. At the same time, "it was quite clear that I had miscalculated the second balloon and not all the people could leave in it," Wetzel said. Instead of continuing to work on the balloon with Strelzyk, he instead started to build an airplane on his own to leave with his family, his wife, Petra, and sons Peter, 5, and Andreas, 2.
But Strelzyk didn't give up. In July 1979, he gathered his wife, Doris, and their sons Frank, 15, and Andreas, 11. They drove to a deserted clearing, set up the balloon and took off around 1:30 a.m. They were headed toward West Germany until the balloon went through a cloud, weighing down the fabric and causing it to descend. They landed short of the West by about 180 meters (590 feet), crashing on the GDR side of the landmine-covered border zone.
When Wetzel heard about the balloon, he knew Strelzyk had nearly succeeded. He also knew that once the Stasi found out about Strelzyk, they'd quickly move on to Wetzel. The partnership was back on in late July 1979.
"The state was probably going to look for us," Wetzel said. "Building a balloon was a quicker and safer option" than building an airplane or waiting for the Stasi to find them.
This time, they had to succeed. So they had to make the balloon a lot bigger.
The men doubled the size of the balloon to 4,200 cubic meters, which would require about 1,300 square meters (13,993 square feet) of fabric. They used everything they could find -- taffeta, umbrella fabric, tent nylon and bed linen. Because officials were looking for people buying large amounts of fabric, the men and their wives drove all over East Germany to acquire the material. Wetzel, who had returned to a full-time job, called in sick from work to sew the balloon night and day, with the help of Strelzyk's older son.
After five weeks, the balloon was nearly done. The men felt like they were racing against time, worried they could be discovered any moment. The forecast on Sept. 15 looked perfect, so the families hurried their preparations, finishing the stitching of the balloon at 10 p.m.
Wetzel and Strelzyk drove to the highest hill near Pössneck to see if the wind was strong enough for flight. It was.
They rushed home to gather their families and the balloon, taking nothing with them beyond school and identification papers. The two families arrived at the launch site around 1 a.m. and waited to be sure they hadn't been followed.
Half an hour later, they started to set up the balloon. Within five minutes, it was fully inflated. Everyone jumped into the basket. They didn't have time to be afraid.
"We were under so much pressure that we just functioned," Wetzel said. "There was no room for any feelings whatsoever."
The flight didn't start smoothly. Wetzel and Frank stood at opposite corners to cut the anchor ropes, but they didn't release them at the same time, causing the balloon to tilt into the flaming burner. The fabric caught fire as the last anchor shot up from the ground and grazed Frank's head. They quickly put out the flames using a fire extinguisher. But a hole in the top of the balloon meant they had to fire the burner the entire flight.
At 2:32 a.m., the balloon soared into the sky, reaching an altitude of 2,000 meters and hitting the 50-km-per-hour winds that pushed it along. There was no way to steer the balloon, and the families were at the mercy of the wind.
No one spoke -- until they spotted three bright searchlights in the distance. It was a border crossing.
It was the next moment that posed grave danger: The burner went out. Efforts to relight the flame only worked for brief spurts. They were out of gas, and the balloon fell rapidly before landing in among the trees.
Had they made it to the West? They didn't know for sure, so they started walking south. Soon they spotted a sign for a power plant called Überlandwerk, something they'd never seen in East Germany. Farm machinery in the building, and the eventual arrival of the West German police, confirmed it. They had landed in Naila, West Germany.
The flight took 28 minutes. They had made it to the West. They were free.
The town of Naila gave the families apartments and aid to get started. Disney bought the rights to their story and released a film, Night Crossing, in 1982. Last year, a German filmmaker released a thriller about the escape, called Balloon.
Ten years later after arriving in West Germany, Wetzel watched the Berlin Wall's collapse on TV.
"I had felt that something was going to happen, but I didn't think it would go that quickly," he said. "The moment was indescribable."
Fiona Weber-Steinhaus translated Wetzel's thoughts from German into English.
This article was written as part of the Goethe-Institut's Close-Up journalists' exchange program and Wunderbar Together-The Year of German-American Friendship. More information can be found at www.goethe.de/nahaufnahme and at #GoetheCloseUp and #WunderbarTogether.