Chernobyl Exclusion Zone, Ukraine: The site of the worst nuclear disaster in history is now open for tours, offering a glimpse into a post-apocalyptic world.
Auschwitz-Birkenau Memorial and Museum, Poland: The remains of the largest Nazi concentration and extermination camp, a sobering reminder of the horrors of the Holocaust.
Hiroshima Peace Memorial Park, Japan: Dedicated to the victims of the atomic bomb in 1945, it's a place for reflection on the impacts of nuclear warfare.
The Catacombs of Paris, France: An underground ossuary holding the remains of over six million people, offering a stark perspective on the city's history of disease and death.
Ground Zero, New York, USA: The site of the September 11 terrorist attacks is now a memorial and museum, paying tribute to the victims.