upplying arms to the world's governments for nearly four centuries, Friedrich Krupp AG Hoesch-Krupp had so much weaponry to display at the World's Columbian Exposition in 1893 in Chicago, that the Essen, Germany-based company needed its own building to house them. Built at a cost of $1.5 million (about $36 million in today's currency), the Krupp Gun Pavilion's star attraction was The Thunderer, shown above. The world's biggest gun, the 47-foot-long, 124-ton cannon lobbed 2,300-pound shells 15 miles, and would soon go from mesmerizing attendees to massacring armies.