Where is the Cathar sign? Beziers. This is the exterior of the Cathedral St. Nazaire in Beziers, a lovely city with a meandering river below a bluff where a lovely Cathar Christian church once was, and where a not-so-lovely conglomerate as reconstructed after the Crusade conflagration stands now - Cathedral St. Nazaire.
The Orb River, and the cathedral from a distance, look picture-postcard. See http://www.creme-de-languedoc.com/Languedoc/city-guides/beziers.php#.UUOhbzdGSho. From the exterior, see the only public reference to history here: "Place de la Revolution" -- Place of the Revolution, dating from Napoleon times -- this time Napoleon III in 1851.
That is a travesty. Where is the memorial to the Christians, Cathar and Roman Catholic, burned, killed in this one scene from the Pope's 13th Century Albigensian Crusade.
Go back to "creme de languedoc". After discussion of the Roman influence there, the site notes this: that in the 13th Century, some 20,000 Christian Cathars mingled with Roman Catholic Christians were killed in the Pope's Albigensian (named for the city of Albi where many lived) Crusade, and that many sought refuge in churches.
This was one of those churches, thousands burned alive. Burn them all, God will know his own, was the watchword, as Cathars and Roman Catholics alike were slaightered. They had lived together in harmony and mutual prosperity for several hundred years, see http://www.cathar.info/1204_origins.htm. They believed in a dualism in theology, as many others also did, but the Catholic Church decided that was wrong. They were right. And so the Cathars and others of differing interpretations of scripture historically also died as heretics for hundreds of years.
Kill them all. God will know his own. See http://www.christianitytoday.com/ch/news/2000/sep08.html