One of the first Obscure Cities stories, the art by Schuiten really makes the story. One of the things to note are the art nouveau touches – most prominently the French curves at the top of the observation window in the bottom panel. French curves are one of the easiest ways to spot art nouveau – a style that grew up in Brussels, where Schuiten was born and trained as an architect. 

(Heavy Metal issue #92, November 1984 – Page 63 The Walls of Samaris by Schuiten)