Russia

Actually, only Nicholas II was ever overthrown. However, there have been rebellions aplenty, and some were assassinated, to be replaced by a more successfully self-assertive ruler. Your question is extremely complex, although you may not have intended it. There are volumes which could be written to give a short answer. I would recommend to you Peter the Great and Nicholas and Alexandra by Richard Massie, as they are well-written, solidly supportable and very informative. In 1613, an assembly of boyars, church leaders and merchants prevailed upon a reluctant Mikhail Romanov to become Tsar. He was all of 16 years of age, and the nation was sunk into a mire known in their history as the "time of troubles." His grandson, Petr Alexeevitch, made Russia into a modern European nation, and began the process by which it became one of the superpowers. I would recommend both books, as he includes enough of the story of Mikhail and his son Alexei who preceeded Petr, and Petr's successors in the first, and gives at least brief notice to the rulers in between in the second book, which is about the final tsar and his wife. Find a good biography of Catherine the Great to cover the middle period, and you will have a good view of the Romanov dynasty.

Of course, you will not have done the period before 1613, but that is why i've said your question is quite complex.

Well, in truth, both Peter III and Paul were overthrown. But that's probably not the kind of information that Tyrius was looking for.

Didn't intended to be complex. Was reading one of my dad's culturally literate books