Central America () is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. Central America is bordered by Mexico to the north, Colombia to the southeast, the Caribbean Sea to the east, and the Pacific Ocean to the west. Central America consists of seven countries: Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama. The combined population of Central America is between 41,739,000 (2009 estimate) and 42,688,190 (2012 estimate). The Central American land mass has an area of , or almost 0.1% of the Earth’s surface. It is part of the Mesoamerican biodiversity hotspot, which extends from northern Guatemala through central Panama. Due to the presence of several active geologic faults and the Central America Volcanic Arc, there is a great deal of seismic activity in the region. Volcanic eruptions and earthquakes occur frequently; these natural disasters have resulted in the loss of many lives and much property. In the Pre-Columbian era, Central America was inhabited by the native American peoples of Mesoamerica, especially the Mayans and the Aztecs. Soon after Christopher Columbus’s voyages to the Americas, the Spanish began to colonize the Americas. From 1609 until 1821, most of the territory within Central America—except for the lands that would become Belize and Panama—was governed as the Captaincy General of Guatemala. After achieving independence from Spain in 1821, the former Captaincy General was annexed to the First Mexican Empire, but soon seceded from Mexico to form the Federal Republic of Central America, which lasted from 1823 to 1838. The seven nations finally became independent autonomous nations, beginning with Nicaragua, Honduras, Costa Rica, and Guatemala (1838), followed by El Salvador (1841), then Panama (1903), and finally Belize (1981). Today, after more than two hundred years of social unrest, violent conflict and revolution, poverty, social injustice and violence are still widespread throughout Central America.