The festival was first held in 1985, and the idea was simple: bring all the regions of Saudi Arabia together in one place so that people - especially children - could see, hear, taste and touch the traditions of every corner of the country. The festival rebuilds the look of old Saudi villages right there in the desert.
Each Saudi region has its own area at the festival. In one corner, you can watch women from Asir paint their houses in the bright geometric patterns called 'Qatt Asiri' - patterns that UNESCO has put on its list of important world traditions. In another corner, craftspeople from Najran weave palm-leaf baskets. In another, blacksmiths from Hail forge metal coffee pots in the old style.
There is non-stop performance. Ardha dancers stamp the ground. Storytellers tell tales from a thousand years ago. Camel races thunder across the sand. Falconers fly their birds. And there is food everywhere - kabsa, mandi, breads of every kind, fresh dates, gahwa coffee.
Children get a lot out of it. Many schools take whole class trips to Janadriyah. Pupils dress in regional clothes, taste foods from places they have never been, and meet craftspeople who can teach them small things - how to weave, how to grind coffee beans, how to spin a falcon's leather glove.