From the 21st century, all the way back to the ancient period, Mexico City is loaded with Historic Sites and Buildings. In world history, pretty much the entire 17th and 18th centuries happened here - or at least passed through.
For constructions older than that, don't miss the section on Archaeological Sites. For anything newer than that, you're in the right place.
There are churches and monasteries and residential palaces - all in the most influential building styles of the time. In fact, people spend a lifetime, right here, still studying all the things that were built.
Many of the most prominent historic sites and buildings are arranged along noteworthy streets, were built on the edges of the city's hundreds of parks and public squares, or they're simply the places where something important happened.
There's not going to be an end either. Things just keep getting more interesting, more involved, and ever deeper. Whatever you're hoping to learn, you should find it here.