Sixty years ago, as the Iron Curtain sealed off Eastern Europe, Teodor Stanca was among millions sentenced to jail, death or forced labour for opposing Communist rule.

Today, as survivors of this dark page of history are getting older and fewer, 80-year-old Stanca says he hopes a Romanian jail-turned-museum will remind future generations that "freedom needs eternal vigilance".

"The Sighet Memorial for the Victims of Communism and of the Resistance", as the museum is known, is the first of its kind in Europe.

More than one million people have visited the memorial in the northern town of Sighetu Marmatiei, which was founded 20 years ago on the site of one of the most notorious political prisons in Romania.

About 200 politicians, priests and intellectuals were held there in secret between 1950 and 1955, when the Communist terror reached its peak in Romania. Fifty-four of them died.

The former jail "prevents people from forgetting those who sacrificed their lives to defend democracy," Stanca, a retired engineer, told AFP at an exhibition dedicated to the student movement he led in 1956 to call for more freedom.

The museum includes a research centre, a memorial to those who resisted and summer schools where young people meet with former political prisoners and historians from around the world.

"We want to inform foreigners and Romanians themselves about the sufferings endured by people living under totalitarian Communist regimes from the end of the Second World War until 1989," poet Ana Blandiana, who founded the museum with her husband, told AFP.

Blandiana's books were banned under Nicolae Ceausescu, Romania's last Communist dictator, who was toppled and executed in 1989.

In Sighet, each cell shows a different aspect of the brutal repression of Communist rule, from the massive surveillance by the Securitate secret police to torture.

Detailed accounts of forced labour remind visitors that tens of thousands of Romanians had to work like slaves building a canal towards the Black Sea.

"Since 1993, even before the archives were opened, we recorded thousands of hours of testimonies from survivors," Blandiana said.

The extent of the suffering had largely been hidden.

"There are two different memories in Europe," said Stephane Courtois, a French historian who edited the bestseller "The Black Book of Communism".

"In the West, we had a glorious memory of Communism -- the Spanish Civil War, the Popular Front, anti-fascism, resistance to Nazism. Here it was the exact opposite. People talk only of terror, torture, misery," he told AFP.

Stalinist purges in the former Soviet Union and Communist repression in Eastern Europe claimed millions of lives in the 20th century, according to historians.

In Romania alone, more than 600,000 people were sentenced and jailed between 1945 and 1989 for political reasons.

Stanca was one of them.

"In the jail, we suffered from hunger, we did not get any medical assistance, we were continuously humiliated," he said.

He was then sent to a labour camp to erect dikes along the Danube river.

"I think only the pyramids were built with such inhumane physical work," he added.

But despite the grim conditions, detainees tried to resist.

"We fabricated paper to write poems by mixing dust we scratched from the walls, a bit of soap and water. If we were caught it meant seven days in the 'black room'," or punishment cell, he said.

Verses were transmitted using Morse code from one cell to the next.

When he was on the verge of dying, his fellow inmates forced bread into his mouth and saved him, he said.

The museum also dedicates several rooms to repression and resistance movements in Poland, the former Czechoslovakia and Hungary.

"In Romania, we discovered that more than 200 revolts of farmers took place against forced collectivisation but had remained unknown to the public," said Blandiana.

"Understanding what took place -- the repression we felt for about 50 years -- you can understand the hangover from this period of totalitarianism in Romania, and why the country still struggles to establish the rule of law and a solid democracy," she added.

The task has not been easy in a country where former Communists and informants still hold key positions in public life.

"This memorial is very important, not only because of the past but for the future," said former Czech political prisoner Petruska Suskova.

"The danger of totalitarian regimes has not disappeared."