In February 2013, a hole opened up beneath a home in Florida, and swallowed a man. Jeff Bush was asleep when a sinkhole opened up beneath his bedroom. Despite the efforts of his brother to rescue him, Jeff was never seen again and his body was never recovered. Professor Iain Stewart travels to Florida to try and understand what killed Jeff, and why the geology of this state makes it the sinkhole capital of the world.
Venture into the danger zone of two volcanic craters posing widely divergent threats. Hawaii's Kilauea is a shield volcano that threatens communities with its slow-but-relentless lava flow, while the Sumatran Sinabung is a stratovolcano delivering carnage via a sudden and explosive surge of superheated gas and rock.