With the recent news about the events unfolding on the Crimean peninsula, we've gotten an influx of questions about the history of Russia, Ukraine and the Crimea. We've decided that instead of having many smaller threads about this, we'll have one big mega thread.

We will have several flaired users with an expertise within these areas in this thread but since this isn't an AmA, you are welcome to reply to questions as well as long as you adhere to our rules:

• If you don't know, don't post. Unless you're completely certain about what you're writing, we ask you to refrain from writing.

• Please write a comprehensive answer. Two sentences isn't comprehensive. A link to Wikipedia or a blog isn't comprehensive.

• Don't speculate.

• No questions on events after 1994. If you're interested in post '94 Russia or Ukraine, please go to /r/AskSocialScience.

Remember to be courteous and be prepared to provide sources if asked to!