1) The first sound film, "The Jazz Singer," was released in 1927 and marked the transition from silent movies to "talkies."

2) The Yangtze River, also known as the Changjiang River, is the longest river in Asia and the third-longest in the world, stretching over 6,300 kilometers (3,915 miles). It holds immense cultural, historical, and ecological significance for China and the surrounding regions.

3) The national animal of Australia is the kangaroo.

4) The ozone layer, located in the Earth's stratosphere, protects us from harmful ultraviolet (UV) radiation.