Civilization – Is it possible to disable wonders

If the one remaining civ has 3 city-states that they have conquered, you can liberate them to get your 3 votes. Otherwise you can't get a Diplomatic victory after you undiplomatically crushed all those city-states. =)

A lot of wonders (if not all of them?) show up as a visible model around the city in which they are constructing / constructed. So if you see a pyramid around a city, you know the the great pyramid is built there.

It takes some practice to know what wonder is what, and it's definitely a very crude way; requires scanning all cities for things that are sometimes very hard to notice. But it does work, I use this method often to know which wonder is being constructed by other civilizations, to avoid working on the same wonder.

Notice that all wonders have different "under construction" and "completed" models.

EDIT: I've found this wonderful page which attempts to catalog all wonders with screenshots of their "under construction" and "completed" models. Still incomplete, but useful nonetheless.