What happened to an infamous pirate city in Jamaica? Also, a grim gulag in Croatia, a wartime subterranean complex in Scotland and a plantation in the Deep South of America caught up in the troubled aftermath of the American Civil War.

Within a dense Polish woodland sits a forgotten complex with an explosive history. Also, grand coastal defences in Ghana reveal a tortured past, a decaying giant that had once promised to kick-start Serbia's industrial revolution, and a site built to keep America functioning in the aftermath of a nuclear war.