The security and customs services at the border of Poland are on constant watch to stop illegal items entering the country. It's their job to detect criminals trying to smuggle items.

Polish history is full of unexplained catastrophes. Though many people have lost their lives, their causes have never been fully established. The Discovery Channel will take a close look at these tragic events, finding new evidence, witnesses, and the latest expert opinions. All this to check the origins of the "greatest Polish catastrophes" and whether they could have been prevented.