Never forget.

That has always been the idea behind teaching the Holocaust in schools and listening to eyewitness accounts. But as we mark the 80th anniversary of Kristallnacht this month and the youngest Holocaust survivors enter their ninth decade, the world is showing dangerous signs of memory loss.

In the United States, the number of neo-Nazi groups has been rising, from 99 in 2017 to 122 in 2018, according to the Southern Poverty Law Center. Fascist groups are brazenly gathering and scoring political victories across Europe, from France and Hungary to Poland and, incredibly, Italy and Germany. Just last year a far-right German politician attacked the very premise of Berlin’s Memorial to the Murdered Jews of Europe, saying, “This laughable policy of coming to terms with the past is crippling us.”

We at Smithsonian profoundly disagree. The work of coming to terms with the past and connecting it to the present is essential. The five stories that follow are about recovering lost history and understanding what happens when innocent young people are caught in the machinery of hatred and war.

Our main story is by Renia Spiegel, a spirited Polish teenager who spent her last days hiding from the Nazis. Her gift to us today is her journal, an eloquent account of a young woman’s consciousness blossoming in the midst of unimagined evil. Three-quarters of a century later, Smithsonian has translated her diary into English for the first time and drawn from the whole text to present her voice, her aspirations, her vivid observations, her rich emotional life. It’s a vital new contribution to our collective memory of the historic tragedy that the world seems on the verge of forgetting.