Top landmarks: Auschwitz
When it comes to the world's best landmarks to see, it's often landmarks related to a happier time in history.
However, I think people should pay a visit to landmarks related to darker but equally important times in history - especially as a reminder of how horrible mankind can be.
That's why I've chosen Auschwitz as a landmark that everyone should see at least once in their lifetime.
Auschwitz - now known as Oswiecim in its Polish name - actually refers to three concentration camps in the area, Auschwitz I, Auschwitz-Birkenau and Monowitz.
The scale of terror imposed by the Nazis all those years ago is still very much evident especially in the Auschwitz I camp which has now been converted into a memorial to those whose lives were brutally murdered because of their race - the most touching is a wall with the photos of all the interns at the camp.
However, it is the sight of the ruins of Birkenau - now called Breznika - that will stand out in one's lifetime, just the scale of the place is unbelievable.
There are former concentration camps all over Germany, Poland and the Czech Republic that will evoke emotions as in Auschwitz but Auschwitz-Birkenau was after all the biggest and most infamous of all the Nazi concentration camps in World War II.