The anus is the opening of the alimentary canal to the exterior at the end of the anal canal.

The rectum leads from the sigmoid colon to the anal canal. This is where faeces is stored.

For clarity, in illustrations(like this one) focusing on the large intestine, it is shown in front of the small intestine.

On other illustrations, the small intestine is shown in front of the large intestine. In fact, the large and small intestines are entwined in the abdomen.