Washington, D.C., is home to the most influential power brokers in the world. But how did we come to call D.C.-a place one contemporary observer called a mere swamp "producing nothing except myriads of toads and frogs (of enormou...

The Mexican War introduced vast new territories into the United States, among them California and the present-day Southwest. When gold was discovered in California in the great Gold Rush of 1849, the population swelled, and settlers p...