International highway system connecting North and South America.
Conceived in 1923 as a single route, the road grew to include a number of designated highways in participating countries, including the Inter-American Highway from Nuevo Laredo, Mex., to Panama City, Pan. The whole system, extending from Alaska and Canada to Chile, Argentina, and Brazil, totals nearly 30,000 mi (48,000 km). Only some 240 miles (400 km) in the Panama-Colombia border area remain uncompleted.