A Belene survivor crosses the bridge across the Danube that connects the town of Belene and Persin island in 2015. Dimitar Dilkoff/AFP via Getty Images) This summer, Tana Ganeva traveled to Belene, Bulgaria's most notorious prison camp, where her grandfather was held in the 1950s. Bulgaria has effectively buried the history of its Communist-era gulags, where thousands were starved, tortured, and killed. Ganeva's grandfather attempted to escape Bulgaria four times, before making it to California. See more stories on Insider's business page. The island of Persin is a bird-watcher's paradise.