This 1793 grave is an early version of the kilogram. It is possible this object, now owned by the National Institute of Standards and Technology museum, was once pirate treasure. NIST Museum hide caption

Fighters with the Movement for the Emancipation of the Niger Delta (MEND), pictured in 2008. The rebel group claimed responsibility for the kidnapping. Pius Utomi Ekpei/AFP/Getty Images hide caption

Captain Edward Teach, better known as Blackbeard, is said to have tucked slow-burning fuses into his beard and lit them on fire before plundering towns for gold and rum. Hulton Archive Circa/Getty Images hide caption