4. The Great Library of Alexandria housed hundreds of thousands of texts detailing the entirety of human understanding
Although not the first library of its kind, with a tradition of the institutions a longstanding practice throughout both Greece and the Near East in ancient times, the Library of Alexandria was nevertheless unprecedented in its scale and scope of ambitions. Believed to have been first proposed by Demetrius of Phalerum, an Athenian in exile, to Ptolemy I Soter, it would not be until the reign of his son, Ptolemy II Philadelphus, the Great Library, as the structure would come to be known, would be constructed. Comprising between 40,000 and 400,000 texts at the height of its prominence, the site became the benchmark of knowledge in the ancient world and elevated the city of Alexandria to become regarded as the capital of learning.
Whilst it is common popular belief today that the Great Library was destroyed as a result of a singular cataclysmic burning, the institution actually endured a slow period of gradual decline which begun with the purging of intellectuals from Alexandria in 145 BCE under the reign of Ptolemy VIII Physcon. Indeed burned by accident by the forces of Julius Caesar during his civil war in 48 BCE, the library continued to decline during the Roman Period due to lack of funding. Ceasing to operate by the mid-third century of the Common Era, it is thought the final vestiges of the once great structure were destroyed between 270 and 275 during a rebellion.