ST. MARY'S CATHEDRAL

Standing atop the upper town, Sainte-Marie Cathedral symbolizes the power of the archbishops who built it in the ^15th century. With its 100-meter long, 40-meter wide, 44-meter high square towers, it is the last Gothic cathedral built in France. Whether you arrive from the east or west of the city, you can admire it from afar, sometimes shrouded in mist, with the Pyrenees in the background; already, your gaze is captured by its imposing volumes. It's an extraordinary building that took almost 200 years to build. As a result, several architectural eras run through it. Its original flamboyant Gothic style evolves into the Renaissance, and borrows a Baroque aesthetic in the part reserved for the canons, the choir. As you enter, you're immediately impressed by the sheer size of the nave, with its 26-meter high vaults.

A true artistic feat, the 113 choir stalls are finely decorated with 1,500 scenes and figures carved from solid oak. The craftsmen have brought to life a veritable picture book. No two stalls are identical. Episodes of famine, biblical and mythological scenes, and legendary references take turns to form a fascinating frieze, making the choir one of the most beautiful in Europe. It is closed by a black and white marble altarpiece created in the ^18th century by Pierre Souffron II. Auch Cathedral is home to a number of treasures: a monumental ^17th-century organ with 3,600 pipes above the façade rose; a second organ donated by Napoleon III and his wife Eugénie; and, above all, 18 windows adorned with sumptuous stained glass by Arnaud de Moles, a ^16th-century master glassworker about whom little is known. Transparency effects, attention to detail with the crumpling and draping of clothes, mastery of light and warm, vivid colors that play with the sun: this ensemble, completed in 1513, is astonishing in its theme and hypnotic aura.

Listed as a UNESCO World Heritage Site, the cathedral is one of the must-see sites on the pilgrimage route to Santiago de Compostela. Whether on a guided or self-guided tour, don't miss this jewel, admirably restored in the blond stone typical of this part of Gascony. To complete your visit, don't miss the Musée du Trésor de la Cathédrale (Cathedral Treasure Museum), an interpretation center showcasing the Cathedral's history and architecture, and featuring an astonishing collection of religious and sacred art objects.