Disclosed is a container, such as an above-ground pool, with an improved porthole. The container can include a base, a side wall joined to the base, and at least one porthole. The porthole can comprise an aperture in the side wall and a generally transparent window sheet attached to the side wall and completely covering the aperture in the side wall. Such a design can be stronger and more durable than conventional portholes. The pool can also have portability and storability characteristics that are superior to those of conventional pools.