Metz, France

"La Lanterne du Bon Dieu" — the Lantern of God. Three Chagall windows, Villon glass, Jacques Villon glass, and the highest Gothic nave in France. Free entry; spend a slow 45 minutes inside on a sunny morning when the light is doing its job.

Shigeru Ban's 2010 contemporary art museum — a hexagonal timber roof modeled on a Chinese woven hat, sitting on a glass-walled gallery floor. Three rotating exhibitions, no permanent collection. The strongest contemporary museum in eastern France and a clean half-day for a high school group trip.

The neighborhood the Germans built between 1902 and 1918 — a grand boulevard of basalt and yellow Jaumont stone leading from the cathedral to the train station, with Bavarian, Tuscan, and Art Nouveau buildings side by side. UNESCO is in the process of inscribing it.

The medieval arcaded square that was the heart of merchant Metz in the 14th century. Walk west to the Moselle quays for the photo every group takes — Temple Neuf on its little island, with the Moyen-Pont in the foreground.

The 13th-century fortified bridge-gate over the Seille — a castle-on-a-bridge that controlled the eastern entrance to the medieval city. Free to walk; the small interior museum is a 20-minute add-on.

Thirty-five minutes north by TER regional train. The capital of the Grand Duchy is a UNESCO old town set on a sandstone bluff with the Bock casemates carved into the rock below — a one-hour cathedral-and-bluff walk and a clean half-day add-on that crosses a border on a school group tour.

Pickpocketing is the realistic risk and concentrates at Metz-Ville station and in the December market crowds. Cross-body bags in front, phones off café tables, Day 1 briefing. Hotels are vetted for 24-hour reception and in-room safes.

Tap water is excellent. No special vaccines required beyond CDC routine. The CHR Metz-Thionville (Mercy site) runs a 24-hour ER to international standards and accepts US travel insurance; serious cases route 90 km southeast to the Strasbourg university hospital.

Coach drops at the Place de la République or the Centre Pompidou-Metz lot; the cathedral and old town are 5-10 minutes from either. The Luxembourg day trip uses the TER regional train — no students on rental scooters at any point.

Lorraine sits in a low-seismic, low-storm zone. Practical concerns are summer heat (museum mornings, shade afternoons), occasional Atlantic rain, and Moselle high water in late winter — none of which disrupts a well-planned student group itinerary.

About 6,500 square meters of glass spanning the 13th to the 20th centuries, including three windows by Marc Chagall in the ambulatory and Jacques Villon's 1957 cycle in the choir.

Metz was annexed by the German Empire in 1871 after the Franco-Prussian War, returned to France in 1918, annexed again by Nazi Germany in 1940, and liberated in November 1944. The Imperial Quarter is the architectural fingerprint.

Paul Verlaine — one of the central French Symbolist poets — was born at 2 Rue Haute-Pierre in 1844. The house is open to visitors and the small museum runs literary programming for school groups.

The Lorraine mirabelle de Lorraine AOC area produces about 80% of the world's commercial mirabelle plum harvest. The annual Fête de la Mirabelle in late August is the city's biggest summer event.

Shigeru Ban's 2010 hexagonal roof is a single piece of laminated timber, woven like a Chinese hat. It uses 16 km of glulam beams and weighs 1,500 tonnes — and there is no structural steel inside the roof itself.