Tuberculosis (TB) Tuberculosis (TB) Active tuberculosis (TB) is very contagious. The World Health Organization (WHO) estimates that one-third of the world's population is infected with the bacteria that cause TB.
With an average elevation of 6,800 feet, Colorado is the highest state in the United States. A mountain lake outside of the skiers dreamland of Aspen, Colorado. The US is bordered to the north by Canada and Mexico to the South. With 50 states of varied sizes, US is considered the largest nation in America.
Of the 100 highest major summits of the United States, only Denali exceeds 6000 meters (19,685 feet) elevation, four peaks exceed 5000 meters (16,404 feet), and all 100 peaks exceed 4012 meters (13,163 feet) elevation.