Why most medieval glass is gone
Wars, iconoclasm, and centuries of weather destroyed 80%+ of medieval stained glass. The cathedrals below kept theirs through luck or removal-and-storage during conflicts. Going specifically to see them rewards the trip; passing through is enough to miss it.
Chartres
Chartres Cathedral 80km southwest of Paris — 152 windows, mostly 12th-13th century. The "Chartres blue" is unrepeatable today (lost glass-coloring technique). Day-trip by SNCF (1h from Paris). 5pm afternoon light optimal for the rose windows.
Paris
Paris Sainte-Chapelle (Île de la Cité) — 1248 royal chapel, 15 enormous lancet windows + rose. Reservations required; queue can be 90 minutes. Notre-Dame's restored windows post-fire reopened 2024–25. Le Marais walking distance.
York
York Minster — Great East Window (largest medieval stained-glass window in Europe), Five Sisters Window, multiple 12th-15th century works. England's deepest medieval-glass collection.
Cologne
Cologne Cathedral — Bavarian Windows, Three Kings Window. Survived Allied bombing because of the cathedral's symbolic protection. Modern replacement windows by Gerhard Richter (south transept) controversial but striking.
Bourges
French cathedral town between Paris and Lyon. Bourges Cathedral 13th-century glass — less famous than Chartres but crowd-free.
Canterbury
Canterbury Cathedral — 12th-century miracle windows, Becket pilgrimage scenes. England's oldest large stained glass. Day-trip from London.
Strategy
Bring binoculars — most windows 20+ meters above floor. Late afternoon (3–5pm) east-facing windows weakest, west-facing strongest. Cathedral lighting often dim — visit 11am–3pm sun. Avoid Sundays during services if visiting for photography.