1) The sunflower is not a single flower but a cluster of small flowers arranged in a spiral pattern.

2) The first graphical web browser, Mosaic, was released in 1993 and played a key role in popularizing the World Wide Web.

3) The name "Bluetooth" comes from the 10th-century Danish king, Harald Bluetooth, who united Denmark and Norway.

4) The Great Wall of China is a UNESCO World Heritage site and one of the most iconic man-made structures in the world. It stretches over 21,196 kilometers (13,171 miles) and was constructed to protect the Chinese empire from invasions during ancient times.