ZANKA, Hungary (Reuters) - They called it the "Plattensee" (flat sea), and for Germans from both sides of the Berlin Wall, Hungary's Lake Balaton was close, cheap and mostly free of spies.
No one knew then their 1960s lakeside holidays would set in motion events that helped bring down the wall dividing them.
As the world recently celebrated the 20th anniversary of the fall of the Berlin Wall, the end of the Cold War and Germany's reunification, Hungarians on the scenic shores of central Europe's biggest lake recalled the decades when crowds of East and West Germans vacationed here, just to be together.
"A West German family of three would rent a four-bedroom house," said Csaba Sall, a local travel agent. "A few days later, we would see three cars in the garden and 10 people on the patio: the eastern relatives."
East Germans started to flock to Hungary after the erection of the Berlin Wall in 1961 to exploit easy visa regulations and security laxer than almost anywhere in the communist bloc.
"The German decision to seal off the borders coincided with an easing of travel policy in Hungary," said Janos Rainier, a historian who directs the 1956 Institute in Budapest.
The Institute studies the events leading to and following Hungary's failed 1956 revolution against Soviet rule.
"After the 1956 uprising, Hungarians relaxed rules to soothe tensions," Rainier said, noting that hundreds of thousands of Hungarians fled to the West in 1956, leaving relatives behind.
Instead of sealing its borders, Hungary secured periodic Western passage for its citizens by issuing visas to Westerners, with no questions asked.
That allowed West Germans to travel to Lake Balaton. It was an easy drive from East and West Germany, with ample services, low prices and few if any spies -- a far cry from East Germany with its informers and Stasi secret police. Tourism flourished.
In 1982, Sall became the private first travel agent to get a license in Hungary. The authorities vetted him for six months, but never asked him to report on the tourists.
"We would rarely know about (the Germans') plans," he said. "They would just come and rent a house far bigger than their needs. They would say the father snored, or some such."
The flow of Germans became stronger toward the end of the 1980s. Handwritten "Zimmer Frei" (vacancy) signs were ubiquitous over most of western Hungary.
"We opened up our home in 1985," said Aranka Hera, who owns a big house close to the lake in Zanka.
"A West German man came, looking for a place for his brother from the East. They rented the rooms and came back every year after that."
Hungary's authorities continued to turn a blind eye to the reunions, although the throngs of German tourists were clearly drawn by more than the swan-dotted waters or the vineyards planted in volcanic soil nearby. In some villages, they far outnumbered locals.
"At the time, I thought a lot about where these reunions might lead," said Imre Csanadi, who led the regional council of Zanka and seven nearby villages for 25 years. "It never occurred to me that they would foretell the end of the system."
That, however, is exactly how it played out.
In the spring of 1989, Hungary signed the Geneva Refugee Conventions, officially restricting weapon use by border guards to self defense. International relations warmed as fast as the weather. Germans went to Lake Balaton in record numbers.
At the end of that summer, Otto von Habsburg, a descendant of the country's last royals, organized the now-famous Pan European Picnic at the Austrian border.
When a few hundred East Germans used that temporary opening to run across the border to Austria, the guards stood by, guns idle.
It was the point of no return.
"It happened quite suddenly," Csanadi recalled. "The summer season ended, but the Germans just didn't go home. Everything was full. The beach, the campsites, even the Pioneer City."
Pioneer City, a vast youth holiday center of slab grey buildings and dinky wooden huts, came to be known as "Lager 3" (German for "Camp 3") in those days, housing over 2,000 German refugees. Two more such centers operated in Budapest.
Csanadi, a faithful communist, ended up hosting a basketball team from Leipzig.
"They slept here because they had nowhere else to go," he said. "Then, when the border opened, they asked me if they could open a few bottles from my cellar. They got good and drunk that night, their last night in Hungary."
The date was September 10, 1989. East Germany's leaders would only crack two months later, but for many, this was the first taste of freedom, and a sure sign change was inevitable.
"The borders were to open at midnight," said Tamas Toth, the housing manager of Pioneer City. "That afternoon the Germans lined up every workable car, flying flags, honking, singing."
"They spent what little money they had left on champagne," Toth said. "At about 9 p.m., they set out behind a police car toward the Western border. Then buses came for the rest of them. By noon the next day, they were all gone."
"They were hugging, crying, thanking us... it was an emotional time."
As the crowds disappeared, the refugees left behind mounds of Red Cross clothes and broken-down cars in the Pioneer City and around. They also left behind memories of a time when business was brisk and Germans plentiful.
"After 1989, business from Germans immediately halved," said Sall, the travel agent. "Today, tourists are mostly Hungarians, and they stay for days, not weeks."
"A few Germans still come out of nostalgia," he added. "Some have even bought houses. But they have changed, Easterners as well as Westerners. We can't really tell them apart any more."
Reporting by Marton Dunai; editing by Michael Roddy