Book excerpt: The United States' boundaries have expanded over the centuries—and at the same time, Americans' ideas about their country have grown as well. The nation the world knows today was shaped by centuries of thinkers and events. When Moses Austin first brought American settlers into Texas in 1820, little did he realize the far-reaching consequences of his action. Despite years of conflict and bloodshed, those settlers would eventually join the United States as a new state, adding nearly a million square miles to America's land. Texas changed the shape of America forever!