Shur

Shur was the principal city of Ribos. The Crown Jewels were kept there. Garron and Unstoffe met with the Graff Vynda-K in the castle of Shur, where they used a large piece of jethrik in their attempt to convince him to buy the planet from them. The Fourth Doctor and Romana I visited the city in search of the first segment of the Key to Time. (TV: The Ribos Operation)
 * Some sources give the name of the city as Shurr.