The world's abandoned structures hold new evidence about the lives and deeds of history's greatest heroes and villains, and using the latest discoveries at these mysterious sites, experts count down the ten most significant. Stories: 10) Presidential Compound, Democratic Republic of the Congo; 9) Hellfire Caves, Buckinghamshire; 8) Villa Guardamangia, Valletta, Malta; 7) National School of Art, Havana, Cuba; 6) Constitution Hill, Johannesburg, South Africa; 5) Oakland Auditorium, Oakland, CA; 4) Eastern State Penitentiary, Philadelphia, Pennsylvania, USA; 3) Maestranza de San Bernardo, Santiago, Chile; 2) Fordlandia, Para, Brazil; 1) Nazi Party Rally Grounds, Nuremberg, Germany