Lanzarote
One of Spain's Canary Islands, this is where Karl spent his Christmas holiday in 2003, causing him to miss two episodes of Xfm Series 3. Prior to his trip, listeners informed him that Lanzarote (or, as one listener put it, "Lanza-grotty") isn't a particularly pleasant place to spend a vacation, as it is a fairly barren, volcanic island. Upon his return, Karl largely agreed with the listeners, saying "there's nowt there" and rating his trip a 6 out of 10.
Lanzarote is home to 36 volcanoes, but Karl suggested that they "keep a couple and fill the rest in."