Cathédrale Notre Dame de Chartres

At just 0.6km, Cathédrale Notre Dame de Chartres is short but deceptively intense — 33m of elevation packed into a brief, breathless effort. The average gradient of 5.5% disguises ramps of 11.1% — the kind of gradient that turns plans into prayers. It's over before the legs know what happened — a short, explosive effort where momentum is everything. Located in Centre, France.