Latin America's mountains extend in a nearly unbroken chain from Mexico to Chile and reach elevations above 6000 m.The valleys of these mountains have seen the evolution of diverse and unique ecosystems, as well as the development of several of the region's most celebrated pre-Columbian civilizations.Today these same valleys contain some of Earth's most rapidly changing landscapes, as urban and agricultural frontiers expand and historical land use changes in response to new pressures from economic globalization.These valleys also face poorly understood threats linked to global climate change.