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.
Leadville, Colorado, often called The Two Mile High City and Cloud City, is the highest incorporated city in the *US at 10,430 feet. *Edit 1: Changed world to US. The highest capital in the world, before the domination of Tibet by China, was Lhasa, with an elevation of 12,087 feet above sea level.