The cube map used on this page is by Emil Persson, but with resolution reduced to 512-by-512.
Drag on either scene to rotate the view.
1. Textured Cube
Here, each of the six images from the cube map is loaded separately. They are combined into an array of materials which is used as the material property for the cube. You can see how the pieces of the cube map match up at the edges.
2. Skybox with Cubemap Texture
Similar to the second example, but it textures the skybox with a single cubemap texture instead of with six separate single-face textures. This uses a ShaderMaterial to implement the cubemap texture.