0:00:07.238,0:00:09.119 2,300 years ago, 0:00:09.119,0:00:11.801 the rulers of Alexandria [br]set out to fulfill 0:00:11.801,0:00:14.196 one of humanity’s most audacious goals: 0:00:14.196,0:00:18.710 to collect all the knowledge in the world [br]under one roof. 0:00:18.710,0:00:19.824 In its prime, 0:00:19.824,0:00:23.623 the Library of Alexandria housed [br]an unprecedented number of scrolls 0:00:23.623,0:00:27.287 and attracted some of [br]the Greek world’s greatest minds. 0:00:27.287,0:00:31.697 But by the end of the 5th century CE,[br]the great library had vanished. 0:00:31.697,0:00:35.227 Many believed it was destroyed [br]in a catastrophic fire. 0:00:35.227,0:00:39.363 The truth of the library’s rise [br]and fall is much more complex. 0:00:39.363,0:00:42.776 The idea for the library came [br]from Alexander the Great. 0:00:42.776,0:00:45.038 After establishing himself as a conqueror, 0:00:45.038,0:00:47.846 the former student of Aristotle [br]turned his attention 0:00:47.846,0:00:52.524 to building an empire of knowledge [br]headquartered in his namesake city. 0:00:52.524,0:00:54.732 He died before construction began, 0:00:54.732,0:00:56.745 but his successor, Ptolemy I, 0:00:56.745,0:01:00.764 executed Alexander’s plans [br]for a museum and library. 0:01:00.764,0:01:03.740 Located in the royal district of the city, 0:01:03.740,0:01:05.266 the Library of Alexandria 0:01:05.266,0:01:08.105 may have been built [br]with grand Hellenistic columns, 0:01:08.105,0:01:09.940 native Egyptian influences, 0:01:09.940,0:01:15.231 or a unique blend of the two--there are [br]no surviving accounts of its architecture. 0:01:15.231,0:01:20.089 We do know it had lecture halls, [br]classrooms, and, of course, shelves. 0:01:20.089,0:01:21.958 As soon as the building was complete, 0:01:21.958,0:01:26.591 Ptolemy I began to fill it with[br]primarily Greek and Egyptian scrolls. 0:01:26.591,0:01:30.842 He invited scholars to live [br]and study in Alexandria at his expense. 0:01:30.842,0:01:34.490 The library grew as they contributed [br]their own manuscripts, 0:01:34.490,0:01:39.695 but the rulers of Alexandria still wanted [br]a copy of every book in the world. 0:01:39.695,0:01:44.332 Luckily, Alexandria was a hub for ships[br]traveling through the Mediterranean. 0:01:44.332,0:01:49.441 Ptolemy III instituted a policy requiring [br]any ship that docked in Alexandria 0:01:49.441,0:01:51.943 to turn over its books for copying. 0:01:51.943,0:01:55.080 Once the Library’s scribes [br]had duplicated the texts, 0:01:55.080,0:01:58.553 they kept the originals [br]and sent the copies back to the ships. 0:01:58.553,0:02:02.094 Hired book hunters also scoured [br]the Mediterranean 0:02:02.094,0:02:03.912 in search of new texts, 0:02:03.912,0:02:06.735 and the rulers of Alexandria attempted [br]to quash rivals 0:02:06.735,0:02:12.173 by ending all exports of the Egyptian [br]papyrus used to make scrolls. 0:02:12.173,0:02:16.274 These efforts brought hundreds [br]of thousands of books to Alexandria. 0:02:16.274,0:02:17.825 As the library grew, 0:02:17.825,0:02:22.436 it became possible to find information [br]on more subjects than ever before, 0:02:22.436,0:02:26.689 but also much more difficult to find [br]information on any specific subject. 0:02:26.689,0:02:32.059 Luckily, a scholar named Callimachus of[br]Cyrene set to work on a solution, 0:02:32.059,0:02:33.851 creating the pinakes, 0:02:33.851,0:02:37.238 a 120-volume catalog [br]of the library’s contents, 0:02:37.238,0:02:39.417 the first of its kind. 0:02:39.417,0:02:40.745 Using the pinakes, 0:02:40.745,0:02:43.888 others were able to navigate [br]the Library’s swelling collection. 0:02:43.888,0:02:46.721 They made some astounding discoveries. 0:02:46.721,0:02:49.414 1,600 years before Columbus set sail, 0:02:49.414,0:02:52.972 Eratosthenes not only realized [br]the earth was round, 0:02:52.972,0:02:55.234 but calculated its circumference [br]and diameter 0:02:55.234,0:02:57.948 within a few miles of their actual size. 0:02:57.948,0:03:01.330 Heron of Alexandria created [br]the world’s first steam engine 0:03:01.330,0:03:03.205 over a thousand years before 0:03:03.205,0:03:06.888 it was finally reinvented during [br]the Industrial Revolution. 0:03:06.888,0:03:13.135 For about 300 years after its founding [br]in 283 BCE, the library thrived. 0:03:13.135,0:03:19.211 But then, in 48 BCE, Julius Caesar [br]laid siege to Alexandria 0:03:19.211,0:03:21.800 and set the ships in the harbor on fire. 0:03:21.800,0:03:26.827 For years, scholars believed the library [br]burned as the blaze spread into the city. 0:03:26.827,0:03:30.314 It's possible the fire destroyed [br]part of the sprawling collection, 0:03:30.314,0:03:32.135 but we know from ancient writings 0:03:32.135,0:03:36.661 that scholars continued to visit [br]the library for centuries after the siege. 0:03:36.661,0:03:41.235 Ultimately, the library slowly disappeared[br]as the city changed from Greek, 0:03:41.235,0:03:42.266 to Roman, 0:03:42.266,0:03:43.172 Christian, 0:03:43.172,0:03:45.177 and eventually Muslim hands. 0:03:45.177,0:03:48.323 Each new set of rulers viewed [br]its contents as a threat 0:03:48.323,0:03:50.786 rather than a source of pride. 0:03:50.786,0:03:52.882 In 415 CE, 0:03:52.882,0:03:56.288 the Christian rulers even had [br]a mathematician named Hypatia 0:03:56.288,0:03:59.956 murdered for studying [br]the library’s ancient Greek texts, 0:03:59.956,0:04:02.379 which they viewed as blasphemous. 0:04:02.379,0:04:06.903 Though the Library of Alexandria [br]and its countless texts are long gone, 0:04:06.903,0:04:09.625 we’re still grappling [br]with the best ways to collect, 0:04:09.625,0:04:10.557 access, 0:04:10.557,0:04:12.506 and preserve our knowledge. 0:04:12.506,0:04:14.737 There’s more information available today 0:04:14.737,0:04:17.383 and more advanced technology [br]to preserve it, 0:04:17.383,0:04:19.040 though we can’t know for sure 0:04:19.040,0:04:22.487 that our digital archives [br]will be more resistant to destruction 0:04:22.487,0:04:25.790 than Alexandria’s ink and paper scrolls. 0:04:25.790,0:04:29.406 And even if our reservoirs of knowledge [br]are physically secure, 0:04:29.406,0:04:32.672 they will still have to resist [br]the more insidious forces 0:04:32.672,0:04:34.439 that tore the library apart: 0:04:34.439,0:04:36.252 fear of knowledge, 0:04:36.252,0:04:39.791 and the arrogant belief [br]that the past is obsolete. 0:04:39.791,0:04:43.967 The difference is that, this time, [br]we know what to prepare for.