Creationism is the religious belief that the universe was created in the way described in religious books. According to Genesis, God directly created life from the nothingness that was before, by fixing the chaos that was.  Other religions have different creation myths.  The first approach is known as creatio ex nihilo, which is the Latin name for creation from nothing.

The idea that God created the world has been taught for thousands of years by writers such as Augustine of Hippo.

Creationism as it is known today started in the 19th century by fundamentalist Protestants who were opposed to the theories that scientists began to put forward about geology and evolution.

In the 20th century, creationist movements also started in Islam and Judaism.

Belief 
Creationists do not believe that all of today's living things came about from simple organisms changing or evolving slowly over time. They  believe that life was created much as it is today, and that one form of life cannot change into another. While biologists and paleontologists say that fossils are different from the life we see today, and can be put into order to show changes over time. Young Earth Creationism says life was created in a short time, in its current form. They point to the Flood of Noah to account for most rock formations and most fossils. There is also an Old Earth creationism.

Christian Creationism 
Young Earth Creationism goes completely against conventional geochronology. This kind of creationism says God created the earth roughly 6,000 or 10,000 years ago as told in Genesis. Young Earth Creationists believe that God created the world in six days (with God resting on the seventh) as the Book of Genesis says.  Young Earth Creationism says that Noah's flood is important to creationism. They argue that "the first buried fossils of each group are complete and complex (complicated), strong support for the biblical concept (idea) that each kind of life was created well designed to multiply after its own kind." They believe that the Bible is literally true (see Biblical inerrancy).  Some people say a problem with this is that fossils appear in layers called strata.  
Fossils that paleontologists believe evolved earlier are found in rocks that geologists think are older.
Fossils that paleontologists believe evolved later are found in different rocks that geologists think are younger.
If fossils were of animals drowned in the flood scientists think they would be mixed together. Christian creationists say this happened because of the Noahic Flood, and point to fossils of animals that died quickly. They offer many defenses. Some of these are:1. Fossils that were buried quickly, as in Lagerstätten. One fossil Creationists talk about is where one fish is eating another fish when it was buried.2. Polystrate fossils are fossils that go through multiple rock layers. Christian scientists say this can't happen if the rock layers were formed quickly3. Bent rock layers are rock layers that are bent in a way that Christian scientists say can not happen over millions of years. Christians say there are a lot of these.Other creationists believe God created everything between 13,000  and 14,000 million years ago.  This is called Old Earth Creationism.

Creationists point to the perfection of Earth's size, shape, and distance as designed by God, and Earth's imperfections as proofs that the Earth is dirtied by humans' sin.

The term creationism can be used with more than one meaning. 
Sometimes creationism means that God created life and evolution did not happen.
Other times creationism means just that God created everything but this could have happened long ago and theistic evolution may have happened.

Liberal Christians do not believe in Biblical inerrancy and say God used evolution to create mankind and other life. This idea is called theistic evolution.

Islamic Creationism 
Islamic creationism is the belief that the universe (including humanity) was directly created by Allah as in the Qur'an. Currently, Islam takes religious texts literally. Many scholars say that Genesis is a corrupted version of God's message. 
There is also a creation myth in the Qu'ran, but it is more vague than Genesis. This allows for more interpretation. Several liberal movements within Islam generally accept the scientific positions on the age of the earth, the age of the universe and evolution.

Islam also has its own form of Theistic evolution, which says that mainstream scientific analysis of the origin of the universe is supported by the Qur'an. Many liberal Muslims believe in evolutionary creationism.

Khalid Anees, president of the Islamic Society of Britain attended a conference called 'Creationism: Science and Faith in Schools'. During that conference, he made points including the following:  There is no contradiction between what is revealed in the Quran and natural selection and survival of the fittest. However, some Muslims, such as Adnan Oktar, do not agree that one species can develop from another. Other Muslims do believe that one species can develop from another.

But there is also a growing movement of Islamic creationism. Like the movement in Christianity, Islamic creationists are concerned that the findings of evolutionary theory might contradict what is written in the Qu'ran.

There are several verses in the Qur'an which some modern writers have interpreted as being compatible with the expansion of the universe, Big Bang and Big Crunch theories:

"Do the disbelievers not realize that the heavens and earth were ˹once˺ one mass then We split them apart? And We created from water every living thing. Will they not then believe?"

"Then He turned towards the heaven when it was ˹still like˺ smoke, saying to it and to the earth, ‘Submit, willingly or unwillingly.’ They both responded, ‘We submit willingly.’"

"We built the universe with ˹great˺ might, and We are certainly expanding ˹it˺."

"On that Day We will roll up the heavens like a scroll of writings. Just as We produced the first creation, ˹so˺ shall We reproduce it. That is a promise binding on Us. We truly uphold ˹Our promises˺!"

Baha'i creationism 
The Bahá'í Faith considers the creation narratives in previous Abrahamic religions to be symbolic and not literal. Bahá'í Faith also accepts that the Earth is ancient. Baha'ullah existed at the same time as Charles Darwin, so was aware of Darwin's works.

Scientific criticism 
Religious communities in the United States encourage the inclusion of supernatural explanations of the origins
of both life and the universe as a whole.
Evolution was not included in school textbooks until the 1960s.
In 1987, the United States Supreme Court acknowledged creationism is not scientific, and
should not be taught in public schools.

Related pages 
 Human timeline
 Life timeline
 Nature timeline
Fundamentalism

References

Other websites 

 Stanford Encyclopedia of Philosophy entry on Creationism
 How creationism works
 Creation and Evolution Both?  Examines whether Biblical creation and neo-darwinistic evolution can be reconciled.
 Evolution, Creationism & ID Timeline  Focuses on major historical and recent events in the scientific and political debate
 Evolution Sciences versus Doctrines of Creationism and Intelligent Design
 . A Guide for Museum Docents
 What is creationism? from talk.origins.
 The Creation/Evolution Continuum  by Eugenie Scott.
 Armies of the Night  by Isaac Asimov.
 Workers have stake in defending science a materialist statement on creationism by The Militant, 2005.
 Edward J. Larson and Larry Witham Leading scientists still reject God in Nature, Vol. 394, No. 6691 (1998), p. 313. Online at Freethought-web.org 
 Creationism: The Hindu View
 Biologos is a Christian organization that sees evolution as factual. 

Intelligent design