In this part of our Chernobyl series, we reach the moment of truth - the day when all of Chernobyl's underlying problems rose to the surface and led to the worst nuclear power disaster in history.

In this episode, we see Chernobyl's beginnings, and just where cracks begin to form underneath the surface.

Before we get into the story of Chernobyl, we explore a few previous nuclear disasters, learn how radiation and nuclear accidents are measured, and find out just how sick ionizing radiation will make you.

It's St. Valentine's Day weekend, and love is in the air. Young people throughout northern Dublin flocked to the Stardust in 1981, drawn by the promise of a disco dancing competition to start at one in the morning. But within an hour of people gathering around the dance floor to start the contest, all eight hundred people in the Stardust would be fighting for their lives against a deadly inferno.

They were some of the best and the brightest in British football. In the mid-to-late 1950s, the Busby Babes were young talented players signed on to Manchester United F.C. by manager Matt Busby to mold into a winning side. And win they did, creeping ever closer to Busby's goal of the European Cup. But on February 6th, 1958, the crash which would come to be known as the Munich air disaster would break the hearts of Manchester United fans, Great Britain, and the sporting world at large.

It was a normal working Saturday at the docks in Hoboken, New Jersey - until it wasn't. After the cotton bales on pier three caught fire so very close to barrels of oil and turpentine, every ship docked along the waterfront was under threat, and not all of them would make it out in one piece.

With World War II raging on throughout Europe, those civilians who were merely trying to survive in their day-to-day lives in southern Italy were on the brink of starvation. They needed food, and to find some they opted to hop a freight train to the countryside to barter for whatever they could find. On March 2nd, hundreds of people either boarded the no. 8017 train at Balvano station with legitimate tickets or snuck into one of the train's many freight cars. The vast majority of those onboard would be dead within hours.

Feeling hot this summer? It could be worse. In January of 1719 during the Great Northern War, six thousand troops from the Swedish army began what should have been a two-day walk back over the Norwegian border to their own empire, mentally and physically exhausted from a four-month-long losing battle. But then the snow came, and what was supposed to be a two-day hike turned into a week-long nightmare.  

One country said it was a tragic mistake during wartime. One country claimed it was a deliberate and heartless act. But one thing was true - whether it was one or the other, the shootdown of Iran Air Flight 655 took the lives of 290 innocent people in July of 1988.

It's time for the yearly school trip - no, not to Washington, DC, or the Grand Canyon or New Orleans. In 1986, as every year before it, the kids in the Basecamp program at Oregon Episcopal School participated in a special trip - a climb up Mount Hood in the Cascade mountain range. But when the group left the school late on the night of May 11th, 1986, to head to Mount Hood for the opportunity of a lifetime, they had no idea nine of them would not be coming back alive.