Overview. If you frequently experience shortness of breath or you hear a whistling or wheezy sound in your chest when you breathe, you may have asthma â a chronic condition that causes inflammation and narrowing of the bronchial tubes, the passageways that allow air to enter and leave the lungs.
1 At 47,958 kilometres (29,800 miles) in total length, the Pan-American Highway is the longest road in the world.  The road starts in Alaska, North America and ends in the lower reaches of South America.
(February 2012). In the United States, each state maintains its own system of state highways. This is a list of the longest state highways in each state. As of 2007, the longest state highway in the nation is Montana Highway 200, which is 706.624 miles (1,137.201 km) long.