An outdoor water garden is an obvious "zen" space - a private spot to meditate and enjoy the scenery. This combination of colors and variety of textures could be easily appropriated for indoor spaces, as well.
Another smaller, simpler tranquil feature. This feature is long and narrow, capturing the space available with a beautiful pond complete with water plants, lilies, and edging plants to accent the soft bow in the otherwise rectangular form.
If you are lucky enough to have a small pond built into your home's landscape then you might want to think about adding real fish to the pond. It's always a treat to add new living things to a tranquil space.