1) The ongoing conflict in Syria, which began in 2011, has resulted in a humanitarian crisis, displacement of millions of people, and international efforts to bring about a resolution and provide aid to those affected.

2) The Earth's core is primarily composed of iron and nickel and is as hot as the surface of the sun.

3) The word "piano" contains three vowels: I, A, and O.

4) The novel "To Kill a Mockingbird" by Harper Lee has been translated into more than 40 languages and has sold over 40 million copies worldwide.