Answer: Lech Walesa is known as the leader of the massive Polish anti-communist movement SOLIDARNOSC (Solidarity) that was established already in 1980. Lech Walesa is a person generally associated with the end of Communist order in Poland in 1990.
Explanation: of course there are other personalities and wider context we have to take into consideration - 1) history of USSR and presidency of Gorbatchev, 2) fall of the Berlin War, 3) negotiations Gorbatchev - Reagan etc etc.
The British victory in the French and Indian War had a great impact on the British Empire. Firstly, it meant a great expansion of British territorial claims in the New World. But the cost of the war had greatly enlarged Britain's debt.
Convention of 1818 and the Haitian Revolution (or Rebellion) resulted in more territory for the United States (C).
The Convention directly resulted in more territory for the United States as Britain ceded all its territory South of the 49th parallel. On the other hand, the Haitian Revolution's contribution to US territory was rather indirect: having lost control over french Caribbean landholding influenced Napoleon Bonaparte’s decision to sell Louisiana. This lead to the Louisiana Purchase (1803) which almost doubled US territory.
What are we figuring out<span />