Spike Island, Co. Cork

A 104-acre island in Cork Harbour. A monastery in the 6th century, a star-shaped fort in the 18th, a convict prison from 1847 to 1883, an internment camp for nearly 1,400 Republican prisoners in 1921. At its peak in 1850, it held more than 2,300 men and boys and was the largest convict depot in the British Empire. In the famine years that followed, around 1,000 inmates died and were buried in a single mass grave on the north of the island. The death rate in 1853 was 12%. In the 1860s the prison authorities buried the entire graveyard under metres of earth, which one of the archaeologists later excavating it called “convenient.” The island is now a museum.