Here's the list of sites that I've been to and the links to my blog posts on the respective places.

Some of the places mentioned below do not have links on them. I have visited these sites, but have yet to write about them (mostly those were visited before I began blogging)!
Sometimes, one place under the UNESCO list would include several sites which are split into multiple blogposts. For eg., the 56 belfries of Belgium & France are listed as 1 in the UNESCO listing! So, here too, it is listed as 1, and within brackets are the links to multiple posts as Part 1, 2, etc...
Btw, our daughter Atyudarini has been traveling with us since she was born, and here's her own list of UNESCO World Heritage Sites - Atyudarini at UNESCO!

BELGIUM (16/16)

1. Belfries of Belgium & France (Ghent, Tournai, Bruges, Mechelen, Ypres, Mons, Antwerp, Namur)

2. Flemish Beguinages (Ghent, Leuven, Bruges, Mechelen)

3. La Grand Place, Brussels (Part 1, Part 2, Part 3)

4. Major Town Houses of the Architect Victor Horta, Brussels 

5. Notre Dame Cathedral, Tournai

6. Stoclet House, Brussels
7. Historic City Centre of Brugge
8. Major Mining Sites of Wallonia (Grand Hornu, Bois du Luc, Blegny Mine, Bois du Cazier)
9. Neolithic Flint Mines at Spiennes
10. The Four Lifts on the Canal du Centre and their Environs, La Louvière and Le Roeulx
11. Ancient and Primeval Beech Forests of the Carpathians and Other Regions of Europe
12. Plantin-Moretus House-Workshops-Museum Complex
13. The Architectural Work of Le Corbusier, an Outstanding Contribution to the Modern Movement

14. The Great Spa Towns of Europe - Spa, Wallonia

15. Colonies of Benevolence - Wortel

16. Funerary and memory sites of the First World War (Western Front)

ITALY

1. Historic Centre of Rome

5. Sacri Monti of Piedmont and Lombardy (Sacro Monte de Ghiffa)

6. Residences of the Royal House of Savoy

7. Cathedral, Torre Civica and Piazza Grande, Modena 

8. Early Christian Monuments of Ravenna 

9. Ferrara, City of the Renaissance, and its Po Delta

10. The Porticoes of Bologna 

1. Vatican City

1. San Marino Historic Centre and Mount Titano

SPAIN

1. Works of Antoni Gaudí, Barcelona (Part 1, Part 2, Part 3)

2. Palau de la Música Catalana and Hospital de Sant Pau, Barcelona

FRANCE

1. Palace & Park of Versailles 

2. Banks of River Seine
3. Cathedral of Notre-Dame, Former Abbey of Saint-Rémi, and Palace of Tau, Reims 

7. Chartres Cathedral

8. Amiens Cathedral

9. Nord-Pas de Calais Mining Basin

10. Routes of Santiago de Compostela in France (Amiens Cathedral)

# (11) Funerary and memory sites of the First World War (Western Front)

# (12) Belfries of Belgium & France (Bethune, Lille, Amiens)

NETHERLANDS

1. Canal ring area of Amsterdam
2. Van Nellefabriek 
3. Mill Network at Kinderdijk-Elshout 
4. Waddensea (shared site with Germany & Denmark)

GERMANY

1. Museuminsel (Museum Islands), Berlin
2. Aachen Cathedral
3. Castles of Augustusburg and Falkenlust at Brühl
4. Cologne Cathedral
5. Roman Monuments, Cathedral of St Peter and Church of Our Lady in Trier
6. Upper Middle Rhine Valley

7. Abbey and Altenmünster of Lorsch

8. Speyer Cathedral

9. Messel Pit Fossil Site 

10. ShUM Sites of Speyer, Worms, and Mainz - Seen the view of Speyer Jewry-Court from atop Speyer Cathedral.

11. Zollverein Coal Mine Industrial Complex in Essen

12. Wartburg Castle

#. (13) Frontiers of the Roman Empire - The Lower German Limes

HUNGARY
1. Budapest, including the Banks of the Danube, the Buda Castle Quarter, and Andrássy Avenue

CZECHIA
1. Historic Centre of Prague (incl. Prague Castle, Old Town Hall & Astronomical Clock, and Vysehrad)

LUXEMBOURG (1/1)
1. City of Luxembourg: its Old Quarters and Fortifications (Part 1, Part 2, Part 3)

GREECE
1. Acropolis, Athens
2. Archaeological Site of Delphi
3. Archaeological Sites of Mycenae and Tiryns 
4. Monasteries of Daphni, Hosios Loukas, and Nea Moni of Chios
5. Sanctuary of Asklepios at Epidaurus 

MALTA (3/3)
1. City of Valletta 
2. Ħal Saflieni Hypogeum 
3. Megalithic Temples of Malta

PORTUGAL
1. Monastery of the Hieronymites and Tower of Belém in Lisbon
2. Cultural Landscape of Sintra (Part 1, Part 2)

1. Venetian Works of Defence between the 16th and 17th Centuries: Stato da Terra – Western Stato da Mar

2. Plitvice Lakes National Park

1. Royal Domain of Drottningholm 

2. Skogskyrkogården

1. Historic Center of Vienna

2. Palace and Gardens of Schönbrunn 

3. City of Graz – Historic Centre and Schloss Eggenberg

4. Historic Centre of the City of Salzburg 

5. Semmering Railway

1. Boyana Church

2. Rila Monastery

Total so far - 115