1) The first computer mouse was invented by Douglas Engelbart in 1964 and consisted of a wooden shell and two metal wheels.

2) The Plitvice Lakes National Park, situated in Croatia, is a stunning natural wonder known for its cascading lakes, waterfalls, and vibrant turquoise-colored waters. It is a UNESCO World Heritage site and attracts visitors who come to explore its picturesque trails and scenery.

3) The ocean covers about 71% of the Earth's surface and contains roughly 97% of the planet's water.

4) The oldest known musical instrument is a flute made from a bird bone, estimated to be around 43,000 years old.