January 27, the anniversary of the liberation of Auschwitz-Birkenau, has been designated by the United Nations General Assembly as International Holocaust Remembrance Day. The UN urges us each year to honor the six million Jewish victims of the Holocaust in Europe, and millions more victims of Nazism in the 1930s and 1940s, and to develop educational programs to help prevent future genocides. So, to answer their call, here are some of the important sites, museums and memorials that pay tribute to those who suffered from the Holocaust, one of the most unfathomable events in human history. Traveling to sites is...