Mont-Louis, City of the Sun-King

Behind its 3km of ramparts, on 35 hectares, the smallest city of the Pyrénées-Orientales hides treasures of defensive architecture from the modern period, recognized by Unesco for its exceptional value since 2008.


Built ex-nihilo between 1679 and 1681 to hold the strategic bolt at the crossroads of the valleys of Conflent, Capcir and Cerdanya, the fortified town of Mont-Louis is a member of the twelve fortifications Vauban red which were registered in 2008 on the UNESCO world heritage list. This international recognition is the translation of the exceptional character of the environment in which the National Center of Training Commando squad - 1st choc (CNEC) evolves since its installation at the Citadel in 1964. It is moreover one of the last military units to occupy a work by Vauban, what makes it actor of this dynamics.

The Citadel

On its headland, the Citadel is the town element of defense. From its creation in 1679, it has military vocation, it counts then 2500 soldiers. Since 1964, it shelters the National Center of Training Commando squad (CNEC) - 1st choc. From now the access is regulated there: you can penetrate only accompanied by guides, during exclusive visits organized by the Tourist information center.

At the assault!

Enter in the military Citadel at the occasion of an exclusive guided visit. For more than 300 years, Mont-Louis is a strong place occupied by the Army. Behind the secret of its ramparts, the Citadel contains an element of unique architecture: the Well of the Convicts and his immense wheel. This visit reveals you the secrets of the history of the place and its construction, and offers the opportunity to penetrate into the military area, the zone usually closed to the public.


Tickets are to be removed 30 minutes before departure of the visit at the Tourist information centre.

The guide waits for you at the time of the visit at the entrance of the Citadel.

The Solar furnace

Although the city does not wear an emblem of the Sun King as we can find there in large numbers in Versailles, many centuries later, the engineer Félix Trombe will make of Mont-Louis the cradle of the solar energy and will restore its naming of "city of the Sun-King". Very interested in the expériences connected to the resistance of materials, the servicemen allowed the installation of the first oven within the Citadel, with a laboratory of the solar energy. The region benefiting from more than 3 000 hours of sun a year, it is quite naturally that the scientists chose Mont-Louis to test works on the solar energy there.


From 1949, professor Félix Trombe implants, in the walls of the Citadel, an immense parabolic mirror which will serve to concentrate the beams of the sun towards a unique point. The heat amounts to it in more than 3 000°C, a temperature never reached otherwise, in long lasting and free of charge. It is then the first solar furnace with double reflection to the world. After several trial years, the solar furnace will be abandoned for bigger structures (that of Odeillo). The oven will then be sold to the municipality of Mont-Louis. We move it of the Citadel towards a bastion of the city to show it.


Since 1993, within the framework of the regional program Hélio-Parc, the SOLAR FURNACE DEVELOPMENT SARL exploitsthe solar furnace in partnership with the CNRS (National Center for Scientific Research) for the scientific research. Faithful to pioneer's tradition of Mont-Louis, this company is the very first to use a solar furnace for industrial and craft productions: cooking of ceramic of art, fusion of the bronze or the aluminum for the manufacturing of everyday or sometimes more original objects as the whistle of the famous Yellow Train.


On the occasion of a fascinating visit, the guides of the solar furnace will reveal you the secrets of the technique and will lead you to the heart of the installations. You will discover to the shop the productions of ceramic of art and bronze realized on the spot.