In San Francisco, California, residents in a luxury apartment block noticed their floor wasn't flat. Experts and witnesses analyse what happened to the building.

Once considered the eighth Wonder of the World, the Kinzua Bridge was the longest railway bridge in the world. But, a freak tornado destroyed it - why did it fall?

What epic engineering error caused flooding in Chicago? Plus, on the east coast of the UK, residents seek a solution for their houses that are falling onto the beach.

What architectural error ruined a Paris landmark? Plus, in Dallas, Texas, soaring temperatures and sunrays blaze and reflect into high-rise apartment building.

What Scottish landmark has a limited timespan with risky consequences? Also, in Liverpool on New Year's Eve a huge fire broke out in a carpark - what happened?

In Maryland, an aging and crumbling sewage system wreaks havoc in Baltimore. Experts and witnesses analyse what caused the major environmental and health problem.

A skyscraper in London risks killing pedestrians when large and heavy bolts from the support structure begin falling to the road below. And, why did a highway in Germany collapse?

America's first space station threatens to fall to earth. And, a miscalculation means strong winds could cause a New York skyscraper to topple over. What happened?

Why did an apartment block in Liverpool resist demolition? And, how did an engineering mix-up in Bristol derail a new bus route? Experts examine what happened.