Merciorum
Prince
Going by Wonder:
Angkor Wat: None (Cambodia IRL)
Big Ben: England.
Brandenburg Gate: Germany.
Chichen Itza: Maya.
Cristo Redentor: Brazil.
Eiffel Tower: France.
Himeji Castle: Japan.
Machu Picchu: Inca.
Mausoleum of Halicarnassus: Greece (though located in present-day Turkey).
Notre Dame: France.
Pentagon: America.
Sistine Chapel: None/Vatican.
Statue of Liberty: America (or France
).
Statue of Zeus: Greece.
Stonehenge: None (was made by pre-Celts, not Celts; located in present-day England, where it is something of an important part of the cultural landscape, so England might not be a totally unreasonable choice here).
Sydney Opera House: None/Sydney.
Taj Mahal: India.
Temple of Artemis: Greece (though located in present-day Turkey).
The Colossus: Greece.
Forbidden Palace: China.
Great Library: Greece/Egypt (built by Greeks in a Greek city, but one located both then and now in Egypt, and was built/prospered under the Greek-but-following-Egyptian-customs Ptolemies).
Great Lighthouse: Greece/Egypt (Ditto).
The Great Wall: China.
Hagia Sophia: Byzantium (although it had minarets put on by the Ottomans, and it was very important to the Ottomans, so a fair case could be made for it being both of theirs).
Hanging Gardens: Babylon (although some new evidence suggests it was actually in Nineveh, which would make it Persian).
Kremlin: Russia.
Louvre: France.
Oracle: Greece (and has one of the best quotes ever for its cut-scene
).
Porcelain Tower: China.
Pyramids: Egypt.
United Nations: None/America (it technically is in international land, and is obviously not "American).
Alhambra: Spain/Arabia (Andalusia=/= Morocco)
CN Tower: None (Canada IRL).
Great Firewall: China.
Great Mosque of Djenne: None/Songhai (it was built before the Songhai took the city over (probably), but it seems fair to assign it to them in the absence of any other West African civs. The current structure dates from 1907, though).
Hubble Space Telescope: America (they have too many wonders. With Greece it's justified, with America it isn't. But since it's an American game, I suppose it's expected).
Leaning Tower of Pisa: None (though often in Florentine territory).
Neuschwanstein: Germany.
Petra: Egypt/Rome (Located in Jordan, built by Egyptians, the temples built by a mixture of Nabateans and Romans).
Terracotta Army: China.
Borobudur: Indonesia.
Broadway: America (seriously, that does not deserve to be a wonder at all).
Glove Theatre: England.
Parthenon: Greece.
Prora: Germany.
Red Fort: India.
Uffizi: None/Florence.
And the nationals:
Circus Maximus: Rome.
East India Company: England/Netherlands.
Hermitage: Russia.
Oxford University: England.
And projects:
Apollo Program: America.
Manhattan Project: America (with help from other countries).
So the wonderless civs are:
Assyria: Library of Ashurbanipal.
Austria: Stephansdom.
Aztecs: Great Pyramid of Cholula.
Carthage: Byrsa Citadel.
Celts: Edinburgh Castle.
Denmark: Roskilde Cathedral
Ethiopia: Lalibela
Huns: There really isn't anything to put here. Sorry, Huns
.
Iroquois: Ditto. Sorry, Iroquois
.
Korea: Jongmyo/Gyeongbokgung.
Mongolia: Registan (shared with Samarkand).
Morocco: My knowledge is poor and Wiki has no answers.
Netherlands: Rijksmuseum.
Persia: Khaju Bridge.
Poland: Sukiennice.
Polynesia: Easter Island Statues (which conflicts with their UI, I know, but what else is there?).
Portugal: Jerónimos Monastery
Shoshone: Sorry Shoshone
.
Siam: Ayutthaya (the whole thing, really, but maybe a specific temple).
Sweden: Visby.
Venice: Doge's Palace/ St Mark's/ A whole host of stuff.
Zulus: My knowledge is poor.
And the ambiguous:
Arabia: House of Wisdom.
Ottomans: Blue Mosque.
Spain: El Escorial.
Angkor Wat: None (Cambodia IRL)
Big Ben: England.
Brandenburg Gate: Germany.
Chichen Itza: Maya.
Cristo Redentor: Brazil.
Eiffel Tower: France.
Himeji Castle: Japan.
Machu Picchu: Inca.
Mausoleum of Halicarnassus: Greece (though located in present-day Turkey).
Notre Dame: France.
Pentagon: America.
Sistine Chapel: None/Vatican.
Statue of Liberty: America (or France

Statue of Zeus: Greece.
Stonehenge: None (was made by pre-Celts, not Celts; located in present-day England, where it is something of an important part of the cultural landscape, so England might not be a totally unreasonable choice here).
Sydney Opera House: None/Sydney.
Taj Mahal: India.
Temple of Artemis: Greece (though located in present-day Turkey).
The Colossus: Greece.
Forbidden Palace: China.
Great Library: Greece/Egypt (built by Greeks in a Greek city, but one located both then and now in Egypt, and was built/prospered under the Greek-but-following-Egyptian-customs Ptolemies).
Great Lighthouse: Greece/Egypt (Ditto).
The Great Wall: China.
Hagia Sophia: Byzantium (although it had minarets put on by the Ottomans, and it was very important to the Ottomans, so a fair case could be made for it being both of theirs).
Hanging Gardens: Babylon (although some new evidence suggests it was actually in Nineveh, which would make it Persian).
Kremlin: Russia.
Louvre: France.
Oracle: Greece (and has one of the best quotes ever for its cut-scene

Porcelain Tower: China.
Pyramids: Egypt.
United Nations: None/America (it technically is in international land, and is obviously not "American).
Alhambra: Spain/Arabia (Andalusia=/= Morocco)
CN Tower: None (Canada IRL).
Great Firewall: China.
Great Mosque of Djenne: None/Songhai (it was built before the Songhai took the city over (probably), but it seems fair to assign it to them in the absence of any other West African civs. The current structure dates from 1907, though).
Hubble Space Telescope: America (they have too many wonders. With Greece it's justified, with America it isn't. But since it's an American game, I suppose it's expected).
Leaning Tower of Pisa: None (though often in Florentine territory).
Neuschwanstein: Germany.
Petra: Egypt/Rome (Located in Jordan, built by Egyptians, the temples built by a mixture of Nabateans and Romans).
Terracotta Army: China.
Borobudur: Indonesia.
Broadway: America (seriously, that does not deserve to be a wonder at all).
Glove Theatre: England.
Parthenon: Greece.
Prora: Germany.
Red Fort: India.
Uffizi: None/Florence.
And the nationals:
Circus Maximus: Rome.
East India Company: England/Netherlands.
Hermitage: Russia.
Oxford University: England.
And projects:
Apollo Program: America.
Manhattan Project: America (with help from other countries).
So the wonderless civs are:
Assyria: Library of Ashurbanipal.
Austria: Stephansdom.
Aztecs: Great Pyramid of Cholula.
Carthage: Byrsa Citadel.
Celts: Edinburgh Castle.
Denmark: Roskilde Cathedral
Ethiopia: Lalibela
Huns: There really isn't anything to put here. Sorry, Huns

Iroquois: Ditto. Sorry, Iroquois

Korea: Jongmyo/Gyeongbokgung.
Mongolia: Registan (shared with Samarkand).
Morocco: My knowledge is poor and Wiki has no answers.
Netherlands: Rijksmuseum.
Persia: Khaju Bridge.
Poland: Sukiennice.
Polynesia: Easter Island Statues (which conflicts with their UI, I know, but what else is there?).
Portugal: Jerónimos Monastery
Shoshone: Sorry Shoshone

Siam: Ayutthaya (the whole thing, really, but maybe a specific temple).
Sweden: Visby.
Venice: Doge's Palace/ St Mark's/ A whole host of stuff.
Zulus: My knowledge is poor.
And the ambiguous:
Arabia: House of Wisdom.
Ottomans: Blue Mosque.
Spain: El Escorial.