From ancient Rome to contemporary Paris, the flexing of military muscle is a longstanding tradition.
Take a look back at Hands Across America, the charity event in which 5 million people formed a human chain across the United States.
Thanks to a new law passed by Congress and signed by President Barack Obama, the once extinction-threatened bison is now the official mammal of the United States.
Get the facts on this decennial population count.
Explore the eight other locales that were once the seats of American power.