1) The term "cloud computing" refers to the delivery of computing services, including storage, databases, and software, over the internet rather than on a local server.

2) The highest-grossing concert tour of all time is U2's "360° Tour," which earned over $735 million in ticket sales.

3) The Appalachian Mountains, running along the eastern coast of the United States, are one of the oldest mountain ranges in the world.

4) The fall of the Berlin Wall in 1989 symbolized the end of the Cold War and the reunification of East and West Germany.