http://www.technologyreview.com/Infotech/20152/

On January 30th, 2008, two undersea cables connecting Europe with Egypt and  the Middle East with India were cut.  These cables were fiber-optic cables providing Internet access to and from the regions.  Immediately large portions of the Middle East and India were without Internet access because these cables were bottle necks for Internet activity.  The article states that undersea cable damage is not rare, more than 50 repairs were made in the Atlantic last year, but Europe and America are connected by many different cables so damage to one does not largely affect Internet activity.

The Internet is a great example of a real network used by billions of people in the world.  The nodes can be computers or servers and the edges are the wires (or signals) that connect the nodes.  This article describes a part of the network where the underwater cables are probably local bridges.  In fact they are very important local bridges, connection huge chunks of the network (in this case countries) together. When the cables were cut, the main connection to the Internet for these countries was lost.  The cables are only local bridges because there are other connections, but they are not as widely used, older, and not as fast.  This is an example of how important it is to have multiple connections in networks in case a connection is lost.  Even in many other applications of computing it is good practice to have repetition in case an important part of the system goes down.