Back in 300 B.C., an exiled ruler wanted to create a central location for all of the world's knowledge. The goal was to have one copy of every book ever written in the world, and more than 100 scholars were housed in a building to collect, copy, translate and publish manuscripts and conduct research.
The building became a museum and a library and went on to hold some of the most important philosophy, math and science of ancient times. Works from Socrates, Homer and others were in the building, and the library held 500,000 papyrus scrolls at its height. It was known as the Great Library of Alexandria, but then it burnt down, and we lost a priceless amount of history and knowledge.
Some say Julius Caesar burned it down. Some say its popularity simply dwindled and it was replaced. Some say it didn't exist at all. Nevertheless, the thought of losing all that ancient knowledge produces the same agreement within everyone: We must preserve Earth's most important sites.
People of every background around the globe agree on the importance of saving Earth's history, and in 1975, 193 countries agreed to create a list of Earth's most significant sites. A dozen historical sites were added in 1978, and the list of UNESCO World Heritage Sites was born. Some of the world's most endangered animals, oldest cities and rarest land formations are protected on the list, and today there are more than 1,000 sites listed across 167 countries. How many World Heritage Sites do you know?