Grenoble's sole vestige of ancient castle or chateau architecture, aside from the temporary royal abode of the French kings and the Dauphins, is a round tower--La Grosse Tour Ronde--now built into the Hôtel de Ville, the only existing relic of a still earlier Palais des Dauphins which in its time stood upon the site of the ancient Roman remains of a structure built in the days of Diocletian.
Grenoble's citadel possesses to-day only a square tower with _machicoulis_ to give it the distinction of a militant spirit. It was built in 1409, but to-day has been reduced to a mere barrack's accessory of not the slightest military strength, a "_colombier militaire_," the authorities themselves cynically call it.
Vauban's ancient ramparts have now been turned into a series of those tree-planted promenades so common in France, but the militant aspect of Grenoble is not allowed to be lost sight of, as a mere glance of the eye upward to the hillsides and mountain crests roundabout plainly indicates.
Grenoble, with its fort-crowned hill of "La Bastille," has been called the Ehrenbreitstein of the Isère, a river which has played a momentous part in the history of Savoy and Dauphiny, but which is little known or recognized by those who follow the main lines of French travel.
Mont Rachet forms the underpinning of "La Bastille" and gives a foothold to an old feudal fortress now built around by a more modern work. Below is the juncture of the Isère and the Drac, and the great plain in the midst of which rests the proud old capital of the Dauphins. The site is truly remarkable and the strategic importance of the fortress was well enough made use of in mediæval times as a feudal stronghold. What its value for military purposes may actually be to-day is another story. The walls of the fortress certainly look grim enough, but it is probable that even the puniest of Alpine mountain batteries could reduce it in short order.
Grenoble, as might be expected of a wealthy provincial capital, is surrounded by a near-by battery of palatial country houses which may well take rank as _chateaux de marque_. Some are modern and some are remodelled from more ancient foundations, but all are of the imposing order which one associates with a mountain retreat. These of course are of a class quite distinct from the countless forts, fortresses, towers and donjons with which the whole countryside is strewn.