Season 15

Exploring a complex in New Jersey infiltrated by a notorious gang, a tranquil Japanese island with a poisonous legacy, and a top-secret bunker in Lithuania raided in the name of freedom.

Exploring a serene institution in Wisconsin seized out of righteous anger, a Spanish settlement stained in innocent blood, and a subterranean lair in France with a disturbing objective.

Exploring Nazi towers in Berlin that were defended to the bitter end by child soldiers, a Chicago institution that was the largest of its kind, and an odd vision in the Malaysian jungle.

Exploring a Dover stronghold transformed during an unprecedented crisis, and a top-secret site in Japan used for wartime missions of no return.

Exploring a towering structure in London on the banks of the river Thames, witness to the city's darkest days, and a Wisconsin farmstead that brewed up a storm.

Exploring a top-secret military base in Michigan linked to an unexplained disappearance, and a California transportation hub that inspired lasting change.

Exploring the nerve centre of a heroic rescue mission in England, a dilapidated mansion in Virginia raided during the Civil War, and a facility in Detroit where a champion made his name.

Exploring a top-secret facility in Scotland besieged by militant protesters, and a small Greek island caught in a chilling web of controversy.

Exploring a Philadelphia venue that set the stage for era-defining artists, a French compound where a staggering deception was launched, and a the scene of a baffling crime in Malaysia.

Exploring a remote Peruvian island besieged by a violent rebellion, a refuge in Nevada that offered hope to its occupants, and a French worker's paradise seized by an invading force.

Exploring a secret New Jersey facility infiltrated by a Soviet spy ring, an island stronghold besieged by the Nazis, and a palatial compound in Peru frequented by the country's elite.

Exploring a secret subterranean network in London that inspired James Bond author Ian Fleming, and an Italian country retreat that was designed to brainwash a generation of children.