> For the complete documentation index, see [llms.txt](https://arch-ecs.gitbook.io/arch/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://arch-ecs.gitbook.io/arch/documentation/world.md). # World The World, the place where all Entities live. The **world stores all its** [**entities**](/arch/documentation/entity.md), it contains methods to create, destroy and query them and handles all the internal mechanics. Therefore it is the most important class, you will use the world heavily. Time to play God. ## Lifecycle ```csharp var world = World.Create(); // Creating a world full of life world.TrimExcess(); // Frees unused memory world.Dispose(); // Clearing the world like God in the First Testament World.Destroy(world); // Doomsday ``` {% hint style="info" %} Multiple worlds can be used in parallel, each instance and its entities are completely encapsulated from other worlds {% endhint %} Best of all, you can create any number of worlds with almost infinite entities. You rarely have so much life and freedom. To be precise,`2,147,483,647` worlds with `2,147,483,647` entities each are possible. ## Customize You can also customize the world a little to suit your needs, for example the initial capacity or how big the [`chunks`](/arch/documentation/archetypes-and-chunks.md) should be:

var customizedWorld = World.Create(
    chunkSizeInBytes: 16_382,              // The base size of each chunk
    minimumAmountOfEntitiesPerChunk: 100,  // The base amount of entities per chunk
    archetypeCapacity: 8,                  // The initial size of the archetype array
    entityCapacity: 64                     // The initial amount of entities
);

{% hint style="info" %} Adjusting this is not absolutely necessary, but can be quite helpful. These are always initial values that Arch uses as a guide. It may well be that Arch deviates upwards in some cases, especially with the `chunkSizeInBytes` or the `minimumAmountOfEntitiesPerChunk`. {% endhint %} ## Good to know Now we have a world. A world with all the prerequisites for creating life, changing it and destroying it. The world has the rudimentary methods on which everything in Arch is based. If you only want to work with them, this is possible and offers one less level of abstraction. {% hint style="info" %} As an alternative, you can also work ONLY with the world. Without abstraction of entities and co. This principle is called [`PURE_ECS`](/arch/documentation/optimizations/pure_ecs.md) and will be looked at later. The following documentation refers further to the abstracted entity API. {% endhint %}


Lifecycle Management	Creating and destroying Entities.	Entity
Structural Changes	Adding/Removing components on Entities	Entity
Modification	Accessing and modifying components on Entities.	Entity
Enumeration	Enumerating/Filtering/Matching Entities.	Query
Bulk/Batch Operations	Executing operations on Entities in Bulk/Batches.	Batch and Bulk
Lowlevel	Working with Archetypes, Chunks and Entities directly without any wrappers.	Archetypes & Chunks
Multithreading	Acessing the JobScheduler to run querys or your own Jobs in parallel.	Multithreading
And much more...	Working with Events, the CommandBuffer or several other features directly!

We'll go into more detail later. But now enough talk, go on. Something is lurking behind the next bush.