OurTimeLines is a website that allows you to enter a specific date into the search engine and then tells you exactly where that moment fits into history, as a whole.
AlternaTime is a website that maintains collections of various types of timelines.
Wikipedia has a list of themed timelines, as well.
Timeline Index: “The Timeline Index : People, Periods, Places and Events in a chronological context.”
Timelines of History: an extensive list of historical timelines.
The History Channel! Search under “world timelines” for a century, a decade, or a year. Check out the map search feature too; this may also be useful.