It was only after her grandmother's death that Maniucha Bikont discovered the full extent of her secret. Lea Horovitz had decided to escape incarceration in Warsaw's Jewish ghetto in 1940 after overhearing two shopkeepers comment "she doesn't look like a zduva" (a "yid") on spotting the Star of David on her coat.

"She realised in that moment she should rip off her badge and buy a new identity," says 26-year old Bikont, sitting in a cafe in central Warsaw as she retells her grandmother's extraordinary, but by no means unique, tale. And so it was that Horovitz survived Nazi-occupied Warsaw hiding behind the make-believe persona of Wilhelmina Skulska, who went on to become a successful writer of detective novels.

Her daughter Anna – Bikont's mother – was well into her 30s when she accidentally stumbled across the truth. But Wilhelmina, by now well assimilated and scared of yet again becoming a victim of repeated postwar antisemitic campaigns, refused to discuss the matter. And when the first Jewish kindergarten in Warsaw since the war opened in 1991, she strongly disapproved of the fact that Bikont was among the first "intakes".

"She had suffered so much because she was Jewish I think she felt she had to do everything to stop her children and grandchildren from suffering the same way. She had spent all her life escaping from her Jewishness," says Bikont. "Suddenly, there was I, her granddaughter, coming home from kindergarten singing Jewish nursery rhymes."

Around 90% of the 3.3 million Jews in Poland at the start of the second world war were killed. In the 90s, says Katka Reszke, author of Return of the Jew, an account of 50 Jews in post-Holocaust Poland, "many experts were predicting the end of Polish Jewry".

The end never came. In 2002, 1,133 Poles identified themselves as Jews. By 2011, that figure had leapt to 7,508, although experts estimate that there are as many as 20,000 people with Jewish roots. And on Friday, Poles took the latest step in the fragile attempts to revive the spirit of what was once the largest Jewish community in the world, with the opening of the Museum of the History of Polish Jews.

The gleaming landmark institute, built on the site of the former ghetto and facing the monument to the Warsaw Ghetto Uprising – the 70th anniversary of which was also marked on Friday – has the potential to be on a par with Yad Vashem and Washington's Holocaust Memorial Museum in scale and importance.

"It is certainly not the end," says Reszke, 35, who unexpectedly discovered her own roots when she was 17. "We're here. We're having babies." She calls the new wave "generation unexpected".

Bikont, a music anthropologist who travels around eastern Europe in search of long-lost folk – often Jewish – music, is part of a new, unforeseen generation that has emerged in Poland since the fall of communism in 1989.

"It is an important part of my identity even though I sometimes feel rather unusual, being one of the few people I know in this homogenous overwhelmingly Catholic land who hasn't been baptised," she says, sitting in Tel Aviv, one of her favourite cafes in central Warsaw.

Barbara Kirshenblatt-Gimblett, a Toronto-born ethnographer who is responsible for the permanent exhibition of the almost 1,000-year history of Jews in Poland, says she hopes it will "form part of a cultural itinerary" and "broaden the historical perspective" of the many visitors who come to Poland in search of their Jewish heritage.

"The majority of organised groups, and especially young people, come for the Holocaust and only the Holocaust. The museum has a very important role to play in changing their itinerary," she says.

Volunteers were out on the streets of Warsaw handing out yellow paper flowers – daffodils that also deliberately resembled the Star of David badges Jewish ghetto residents were forced by the Nazis to wear – to commemorate the uprising anniversary. Inside the sand-coloured interior with its undulating passageway and glass panels, dignitaries including rabbis and Jewish scholars from around the world as well as survivors of the ghetto uprising – in which in 1943 thousands of residents rose up against the Nazis in a stand-off that lasted for almost a month, and a year later inspired the Warsaw Uprising – mingled to hear classical music and commemorative speeches in rooms that smelt of fresh paint and varnish.

Yet in the 20 years it has taken for the museum to be realised, smaller groups have been taking steps towards what some call a revival of Jewish life, and others prefer to describe as a delicate reconnection with it. As well as the reopening of synagogues and Jewish theatres, an annual Jewish festival in Krakow and Warsaw's Singer theatre festival, citizen's initiatives have been launched to look after the thousands of Jewish cemeteries across the country, while choirs have been reviving Jewish music. This has all contributed to reshaping the long-standing image of Poland as a massive Jewish graveyard, the site of all the Nazi extermination camps.

Malgorzata Sledziewska, the deputy head teacher at the humanist Jacek Kuron secondary school in Warsaw says it is part the school's individual attempt to "pick up the threads of forgotten history in a country that was ethnically-cleansed", that it is offering pupils Yiddish lessons. "The take-up is strong," she says.

On Poznanska street, the Tel Aviv cafe opened in 2010. Its owner, Malka Kafka, who is Jewish and in her late 30s, says she opened it out of a desire "to be openly Jewish" and to dispel certain myths held by some Poles, about Jews with whom they have little contact. "It was to say 'Hi, we are here and this is more or less how our life looks'. It's not side curls and robes and guys in beards, like the Polish stereotype," she insists.

The need to dispel stereotypes and encourage Poles to recognise their Jewish past was underlined by a recent survey published by the daily Rzeczpospolita, in which 61% of the 1,250 17- to 18-year-olds polled, said they would be unhappy if they discovered their boyfriend or girlfriend were Jewish, while 45% said they would prefer not to have a Jew in the family and 44% would not like to have a Jewish neighbour.

"I am shocked, especially when you consider that we're talking about Warsaw youths, who travel widely these days, but I think it's an expression of how much of the history of Jews in Poland has been obfuscated," says Jan Gross, a Polish historian at Princeton University, who has often been vilified by Poles for daring to confront them with their own sinister chapters of antisemitism.

Krystyna Budnicka, a survivor of the ghetto who was smuggled out via its sewer system but lost her entire family, insists she has seen a shift in attitudes towards Jews.

"At least from a political point of view it is improper to be an antisemite, but it will be harder to change the wider mentality, despite the tragedy of the Shoah," says the 81-year-old, who also assimilated after the war to ensure her survival.

She welcomed the symbolism of solidity and renewal offered by the museum for modern Warsaw as she viewed the former ghetto site from the window of her 14th-floor apartment and recalled how the entire city was burnt to the ground by the Nazis.

"The entire topography of Warsaw changed. There is nothing left of my childhood Warsaw, nothing to which I have a connection," she says. "My kindergarten, my school, our house – even the streets they were on – all gone. The only place I can go to where I am not disoriented is the graves where my grandparents are buried. At least when I go there, I know for sure that my parents would have once stood there."