A web page is located using a URL (Universal Resource Locator). Universal Resource Locator is also known as web address.
It basically refers to a web resource which is meant for the specification of its location on the network of computer. It is also a mechanism through which information can be retrieved.
This region is thus called because of its rich coal field and the iron and steel plants that have come up around them. Rhur valley is a major Industrial hub of West Germany.