Afghanistan, a landlocked country in the heart of Central Asia, is one of the most isolated places on Earth. This isolation has posed huge logistical challenges for the United States. Hundreds of shipping containers and fuel trucks must enter the country every day from Pakistan and from the north to sustain the nearly 150,000 U.S. and allied forces stationed in Afghanistan, about half the total number of Afghan security forces. Supplying a single gallon of gasoline in Afghanistan reportedly costs the U.S. military an average of $400, while sustaining a single U.S. soldier runs around $1 million a year (by contrast, sustaining an Afghan soldier costs about $12,000 a year).