At the Auschwitz-Birkenau Memorial in Poland, a quote on the wall of one
of the cell blocks reads, "Those who do not remember the past are
condemned to repeat it." These words are attributed to George Santayana,
and they help explain why the former death camp is still open for public
viewing 74 years after it was shut down. Historical amnesia was a real
danger after the Holocaust, and with so many other tragedies that have
followed, it's still a threat today.