I get about 27 (I may have overlooked some places in France).Belgium
La Grand-Place, Brussels
Mont-Saint-Michel and its BayGermany
Prehistoric Sites and Decorated Caves of the Vézère Valley
Place Stanislas, Place de la Carrière and Place d'Alliance in Nancy
Pont du Gard (Roman Aqueduct)
Strasbourg – Grande île
Cathedral of Notre-Dame, Former Abbey of Saint-Rémi and Palace of Tau, Reims
Paris, Banks of the Seine
Historic Centre of Avignon: Papal Palace, Episcopal Ensemble and Avignon Bridge
Historic Site of Lyons
Routes of Santiago de Compostela in France
Belfries of Belgium and France
The Loire Valley between Sully-sur-Loire and Chalonnes 9
Le Havre, the City Rebuilt by Auguste Perret
Fortifications of Vauban
Nord-Pas de Calais Mining Basin
Palaces and Parks of Potsdam and BerlinGreece
Museumsinsel (Museum Island), Berlin
Upper Middle Rhine Valley
Archaeological Site of Mystras
Archaeological Sites of Mycenae and Tiryns
Historic Centre of FlorenceThe Netherlands
Piazza del Duomo, Pisa
Historic Centre of Siena
Seventeenth-century canal ring area of Amsterdam inside the Singelgracht
Is it me, or is France seriously overrepresented?
I really wonder how Le Havre gets on the list (it's mostly boring-looking concrete buildings. Sure, the architect is a significant name in the field, but should we include Le Corbusier's ugly suburban housing projects too so we can never demolish the eyesores?).
At the very least I'd add Nafplio in Greece and the Dresden Altstadt in Germany.
The city center of Kopenhagen probably also belongs on the list.