1) The unicorn is the national animal of Scotland.

2) The largest known dinosaur, Argentinosaurus, weighed around 70-100 tons and measured up to 100 feet in length.

3) The first successful mass-produced personal computer, the IBM PC, was introduced in 1981 and played a significant role in popularizing the use of computers in homes and offices.

4) The Treaty of Tordesillas, signed in 1494, divided the newly discovered lands outside of Europe between Spain and Portugal, leading to the colonization of the Americas.