Texas is the second-largest state in the United States. It covers more than 268,600 square miles. Spain was the first European power to lay claim to Texas and the state also flew the flags of France and Mexico before gaining its independence in 1836. Texas borders Mexico along the Rio Grande and embraces mountain ranges and canyons to the west; lakes, plantations and pine forests to the east; plains to the north; citrus groves, Gulf of Mexico beaches and low-lying alluvial plains to the south; and rolling hill country and clear natural springs at its heart. Its wealth stems from its vast oil reserves. Its largest cities are Dallas, El Paso, Fort Worth, Houston, San Antonio, and its capital city, Austin. Texas was annexed to the United States as the 28th state on December 29, 1845.