The city closest to the prime meridian is London. The prime meridian runs through the Royal Observatory in the town of Greenwich, which is in southeast London.
In the past, the location of the prime meridian — 0 degrees latitude — was often arbitrary. A number of countries, including France and China, selected their capitals as being host to the prime meridian. Since maps are referenced against the prime meridian, having more than one was a source of some confusion, particularly when using maps from different countries.
An international convention was held in 1884, at which time Greenwich was selected as the location of the single official prime meridian.
Very few large cities lie close to the prime meridian, aside from Aberdeen, Scotland, Paris, several other French cities and Algiers. It then passes through an area of Western Africa that is relatively sparsely populated.