| colonnade |
7 |
| Colorado |
1 |
| colosseum |
4 |
| Colosseum in London |
1 |
| Colosseum in Rome |
2 |
| Colossus of Apollonia Pontica |
5 |
| Colossus of Rhodes |
5 |
| Columbian Exchange |
1 |
| column |
3 |
| coma |
1 |
| comb |
3 |
| Comecon |
4 |
| Cometopuli Dynasty |
1 |
| Comintern |
3 |
| commemorative coins |
2 |
| commerce control office |
1 |
| common (Eurasian) crane |
1 |
| common (Eurasian) spoonbill |
1 |
| common buzzard |
1 |
| common pheasant |
1 |
| communism |
8 |
| Communist Bloc |
13 |
| Communist Era |
43 |
| communist regime |
20 |
| Comnenus Dynasty |
3 |
| Como |
1 |
| computer game |
1 |
| concentric circles |
1 |
| concretion |
1 |
| Confederation of Employers and Industrialists in Bulgaria |
1 |
| conference |
3 |
| Confluence Museum |
1 |
| Congress of Byzantine Studies |
1 |
| Connie Lord |
1 |
| conservation |
9 |
| Constanta |
8 |
| Constantiana Daphne |
1 |
| Constantine Angelus Ducas (Constantine Angelos Doukas) |
1 |
| Constantine's Bridge |
8 |
| Constantinople |
48 |
| Constituent Assembly |
1 |
| Constitution Day |
1 |
| Constitution of 1947 |
1 |
| Constitution of 1991 |
1 |
| construction works |
51 |
| continent |
1 |
| contraband |
9 |
| Contributions to Bulgarian Archaeology |
1 |
| contubernium |
2 |
| Convention on the Protection of the Underwater Cultural Heritage |
4 |
| conversion to Christianity |
2 |
| Copenhagen |
1 |
| copper |
25 |
| Copper Age |
63 |
| copper coin |
4 |
| copper coins |
5 |
| copper mining |
4 |
| copper ore |
3 |
| copper vessel |
1 |
| Corabia |
2 |
| coral bleaching |
1 |
| Coral Sea |
1 |
| corals |
2 |
| Corinth |
1 |
| Corinthian helmet |
1 |
| Corinthian Order |
1 |
| Corinthian pottery |
1 |
| Cornerstone of Peace Monument |
1 |
| Corrado Catesi |
1 |
| corruption |
2 |
| corruption in Roman Empire |
1 |
| corslet |
2 |
| cosmetics |
1 |
| Cosmographia) |
1 |
| Cossacks |
1 |
| Costoboci |
3 |
| Cotai Strip |
1 |
| Council of Europe |
2 |
| Council of Minister |
1 |
| Council of Ministers |
5 |
| councilors |
3 |
| Count Amadeus IV of Savoy |
2 |
| Count Louis I of Blois |
1 |
| Count Luigi Ferdinando Marsili (Marsigli) |
1 |
| counter coup |
1 |
| coup d'etat |
2 |
| court |
6 |
| cow |
1 |
| crab |
1 |
| crafts |
5 |
| craftsmanship |
2 |
| craftsmen |
4 |
| Craiova Treaty |
1 |
| crane |
3 |
| cranial amulet |
2 |
| cremation |
9 |
| Cretaceou |
1 |
| Cretaceous |
1 |
| Cretan Revolt |
1 |
| Crete |
9 |
