0451

The code 0451 unlocks the first locked door in Deus Ex games.

Origin
The number first appeared in the game System Shock (as 451) and its sequel System Shock 2 (as 45100) developed by. It is a reference to Ray Bradbury's dystopian novel , in which it represents "the temperature at which book-paper catches fire and burns". 0451 was also the door code to access the Looking Glass Studios offices.

The code 0451 has since appeared in numerous other games developed by former Looking Glass employees, including Deus Ex, Bioshock, Dishonored, Prey, and others.

In Deus Ex games and books

 * In Deus Ex, the code 0451 opens the comm van near the UNATCO Headquarters.
 * Deus Ex: Invisible War does not have enterable codes, but the protagonist Alex D starts in the dorm room 451 of the Seattle Tarsus Academy.
 * In Deus Ex: Human Revolution, the code 0451 opens the elevator in David Sarif's office. It is used again as the first code in The Missing Link DLC.
 * Also, a direct reference to the Fahrenheit 451 author Ray Bradbury is made through an announcer in the Detroit Police Station, asking for "detective Bradbury in office 451".
 * In Deus Ex: The Fall, the code 0451 opens the door to Mikhail Kontarsky's hideout in Hotel Novoe Rostov.
 * In the book Deus Ex: Black Light, Adam Jensen wakes up from coma in Facility 451 in Alaska.
 * In Deus Ex: Mankind Divided, the code 0451 unlocks the first door encountered during the Dubai mission. A Heated Combination achievement is awarded for entering the code instead of hacking the lock.
 * Another reference to 451 is made in a Picus TV news report that mentions a Cista Airlines 451 plane crash.
 * As another reference, an email found in a computer in the Time Machine with subject line "Restock" refers to a shipment of rare books on train F451. The sender of the email, Brad Burrie, is a reference to the author, who wrote the book Fahrenheit 451.
 * In Deus Ex GO, it is the code needed to access Novak's secret lab.

In real life

 * Jonathan Jacques-Belletête, art director of Deus Ex: Human Revolution and Deus Ex: Mankind Divided once had a flight number 0451. He wrote about that on Twitter.