China now boasts seven of the 10 longest bridges in the world, all built within the past decade. Such engineering feats were once mainly the province of the United States, which for much of the latter half of the 20th century boasted most of the longest bridges in the world. Here are the 10 longest bridges in the U.S., and no matter how well traveled you are, four or five of these bridges will come as a surprise.
There are two types of neck braces: soft and rigid. A soft cervical collar is made from thick foam rubber covered in cotton. It is used to support your neck and control pain after an injury (e.g., whiplash).
Today's braces are very high-tech appliances. Over time, braces align and straighten your teeth. Here's how they do it: Braces have three basic parts: 1  Brackets made of metal or ceramic. 2  A bracket is attached to each tooth. 3  Bonding material (glue) or a metal band. 4  This is what attaches the bracket to the tooth.