Civilization – the graphs

In the unit overview (selectable from the top-left button), you can either double-click a unit - to select it and center your view on it - or you can click a unit and then, in the lower-left unit info box, either click its portrait or its name.

As far as I know there is no way to get an immediate overview of where all your units are, which is a shame - I would also be interested in something like that. They don't even appear in the mini-map in any form until after you select them...

You can find more information about the unit list (for example, what do the colors mean) in my answer to another question.

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.