The seven defendants were charged with conspiring to "maliciously damage and destroy by means of an explosive" the FBI building in North Miami Beach and the Sears Tower in Chicago.

NPR: U.S. Arrests 7 Accused of Chicago Bomb Plot

Duffy and Donohue wanted its business, and so did Eurex of Frankfurt, the world's largest derivatives exchange, which set up a U.S. unit in the Sears Tower between Chicago's two exchanges.

FORBES: Up From the Pits

Of the top 10 tallest buildings in the world right now, the only U.S. property is the Willis Tower (Sears Tower) in Chicago standing at 1, 451 feet.

FORBES: China's Tallest Building Gets Even Bigger

That was surpassed when the World Trade Center arrived in 1973, but two years later, Chicago's Sears Tower became the tallest at 1, 454 feet.

FORBES: World's Tallest Towers

In 1974, Chicago sealed its reputation with the completion of the Sears Tower, then the world's biggest building.

BBC: Chicago��s celluloid city