New discoveries reveal how a variety of mysterious deserted engineering projects were built and why they were abandoned. Later, experts reveal a possible cover-up attempt of what really happened on a strange, desolate island near Greece.
Experts investigate the demise of historically flourishing communities -- Pablo Escobar's sprawling compound, an elaborate fairy tale estate and a deserted city that was once home to thousands. Eerie revelations and new discoveries reveal the reasons behind such dramatic declines.
New discoveries reveal various deserted, underworld engineering projects -- from a terrifying sea fortress to a strange complex of towers in a forest of ice. Experts explain why they were built and why they were eventually abandoned.