21st century
The 21st century, defined in the calendar of Earth as the period from 2001 to 2100, was a decisive turning point in Human history. After World War III devastated large parts of Earth placing Humanity in near-extinction, Zefram Cochrane made his historic jump to Warp 1 with the Phoenix making First contact with the Vulcans, ushering in a renaissance of peace, unity and development for Humankind. As well, in the latter decades of this century, this was the era of Humanity's earliest space explorations to nearby star systems. (; ; ; )

Decades

Major events 

 The Nomad prototype space probe is launched from Earth as the planet's first interstellar vessel to seek out new life. During its mission, Nomad is damaged by a meteoroid and loses contact with Earth. ()

 Correcting a temporal incursion, the deployment of a Xindi bio-weapon from the future to wipe out Humanity is closely averted with the help of a . ()

 Outcry over deaths and circumstances leading to the Bell Riots forces the United States of America to focus on social problems. This circumstance turns out to be a crucial milestone in the prehistory of the Federation. ()

 Having started in the 1930s, the Xindi Civil War ends with the destruction of Xindus. The Sphere-Builders start to make appearances to the survivors of the Xindi and begin to manipulate them into unknowingly assisting in the transformation of the Delphic Expanse. (). Also, the National Aeronautics and Space Administration launches the Charybdis spacecraft in 2037. ()

 The Andorians first arrive on the class D planet they call Weytahn, beginning to terraform and colonize it. ()

 World War III ends with a nuclear holocaust resulting in the deaths of some six hundred million Humans. Earth begins its long journey towards recovery. ()

 Zefram Cochrane, the inventor of warp drive on Earth, conducts his first test flight with the Phoenix. The Vulcans, who, coincidentally, have the vessel the  in the Sol system, witnesses Cochrane's warp flight, and immediately initiate First Contact with Earth within hours of this demonstration of Human warp capability. (; )

 The United Earth Space Probe Agency launches Friendship 1. ()

 Under the terms of the Treaty of 2097, Weytahn is officially claimed by the Vulcans, who call it Paan Mokar. ()

Events without specified years 
 The species known as the humpback whale becomes temporarily extinct at some point during this century on Earth. ()
 Meanwhile, Earth's ozone layer deteriorates and the surface of the planet is flooded with ultraviolet radiation. ()
 A new age of medicine is heralded on Earth after Pyong Ko discovers the genetic sequence for inhibiting the growth of cancer s. ()
 Ancestors of Gary Mitchell on his maternal side begin to develop an aptitude for extra-sensory perception. ()
 While jointly taking care for the Ocampa on their deserted homeworld in the Delta Quadrant, the Nacene Suspiria leaves . She takes several hundred Ocampa with her, intending to develop their telepathic abilities to a greater extent than the male Caretaker was willing to do. ()
 Progeria is eradicated this century. ()
 The House of Mogh acquires a family bat'leth which will be passed down through ten generations. ()
 An ancestor of Talas is enlisted into the military. ()
 In the aftermath of the nuclear holocaust, there were nuclear winters on Earth. ()

 The Chrysalians enter into an era of peace which will last until at least 2366. ()
 Mizar II is conquered. Over the next three centuries, the planet will be conquered five more times. ()
 The gaseous-core fission reactor of a waste ship becomes inactive. ()
 On the Ullian homeworld, an individual is treated for telepathic memory invasion. Until 2368, this is the last time that someone received treatment for this form of rape. ()
 The Moneans discover and settle on an artificially coherent planetoid of water, which they termed the Waters. ()
 The Vissians start using trinesium to construct starship hulls. ()
 The Second Civil War is fought in the United States. ()

Mid-21st century
 The title of Klingon emperor is dissolved. ()
 The draco lizard on Earth becomes extinct. ()
 Colonists from Earth settle on a planet in the Cepheus system which they later name Terra 10. Shortly thereafter intersat code becomes outdated. ()

 The grandfather of Malcolm Reed is enlisted into the Royal Navy. ()
 The  symbiont sees a wheeled wheelchair for the last time, until 2370. ()
 The Skorr Alar leads his race into a new era of peace. ()
 Cristóbal Rios dies in Morocco in a bar fight over medical supplies. Some time later Teresa Ramirez dies. ()

Late 21st century
 Four wars are fought between Human and the Kzinti. ()
 , an old British Royal Navy nuclear submarine is trapped under an ice shelf and sinks after hitting a mine left over from "one of Earth's world wars." ()
 At some point, physicians cease administering barium to patients with stomach troubles for the purpose of taking X-rays. ()

Notes
According to show runners, Spock was wrong and that Eugenics Wars happened much later during 21st century. Terry Matalas: "We discussed endlessly. We came to the conclusion that in WW3 there were several EMP bursts that kicked everyone back decades. Records of that 75 year period, the 90s on were sketchy. Maybe Spock was wrong? No easy way to do it if you want the past to look and feel like today. Maybe because in 1967 they didn't anticipate the show still going for another 6 decades." Aaron J. Waltke added: "There's also the ripples of the Temporal Cold War shifting the Prime Timeline in Enterprise — at least until the Temporal Accords put an end to that wibbly wobbliness."

Appendices

21st century productions 
 
 (in part)
 (in part)
 (in part)
  (in part)
 
 (in part)
 (in part)
 
 (in part)
 (in part)
 (mirror universe) (in part)

Apocrypha 
According to a Hewlett Packard Enterprise commercial intended to tie-in with , at the beginning of the 21st century was in need of a new way to keep up with the data from over thirty billion devices. Scientists from Silicon Valley made a breakthrough, , which changed the basic architecture of computers, and by doing so changed the world. The Machine was said to have been the path of every new technology for the next 250 years.

External links 
 
 

cs:21. století
de:21. Jahrhundert
es:Siglo XXI
fr:21ème siècle
ja:21世紀
nl:21e eeuw
pl:XXI wiek
pt:Século XXI
ru:21 век
sv:2000-talet