1) The unicorn is the national animal of Scotland.

2) The first modern Olympic marathon race was held at the 1896 Olympics in Athens and has since become one of the most iconic and challenging events in athletics.

3) The world's largest volcano, Mauna Loa in Hawaii, is also one of the most active.

4) The construction of the Great Wall of China began in the 7th century BC and was completed over several centuries, spanning thousands of miles.