If we think of cardboard at all, it's usually thought of as superfluous, something to send to recycling (as in all those boxes from Amazon purchases.) Sometimes we can re-use packing boxes, sharing from one household who has moved into their home with another just starting their moving process. Kids and pets make good use of some of the cardboard.
However, creative minds think "beyond the box" and have turned cardboard into delightful pieces of art. Some of my favorites include pieces from an exhibit at the Exploratorium including these houses and an entire town: