I've been in Chandigarh for almost a month now and now feel that I understand Nek Chand's Rock Garden (where I'm doing some voluntary work) well enough to say something about it.
To get the official overview check out the Nek Chand Foundation website. The garden itself is more vast than the public ever see; as with all the best visitor attractions all the best stuff happens behind the scenes, and it is a great privailage to visit the workshops where the sculptures are being made and see how it is done, and to have access to the aerial walkways which snake their way through the garden, mostly out of view from the public. The garden gets 3000 visitors a day on adverage, and only the most adventurous and inquisitive ever venture into the forbidden places behind the closed iron gates and over the concrete walls; those are secret places, it is a secret, enchanted garden, with no end of places to explore and curious half built structures to give you plenty to think about and delightful insights into the mind of Nek Chand himself, who directs the ongoing construction of the garden without plans or even sketches, and has no qualms about changing his mind and starting again, or allowing things made to fall into disrepair half finished, and directing his attention elsewhere: his thoughts turn to concrete before they are fully formed and are left behind as his imagination wanders across the park. He has a unique mind, and a quiet charisma.