The Cathédrale Saint-Étienne dominates the skyline of Metz with its honey-gold limestone facade and one of the tallest Gothic naves in Europe. Locals call it the "Lantern of God" for the sheer area of its stained glass — over 6,500 square metres — which gives the interior an extraordinary luminous quality on a sunny day. Construction began in 1220 and continued for nearly three centuries.
Inside, the eight centuries of glasswork are the main attraction: Hermann von Münster's medieval rose window above the western portal, Renaissance panels in the choir, and 20th-century compositions by Chagall and Villon that bring the building's history into the modern era. The Chagall windows in the ambulatory and north transept are especially good in late-afternoon light, when the blues and greens seem to float inside the Gothic stonework.
Allow at least an hour, more if you want to trace the glass properly rather than just step into the nave. Entry is free; guided tours are usually in French, with occasional English options. Climbing the tower, when accessible, is one of the best ways to see the city from above.