Quoted from "Insight Guides Vietnam":
For anyone travelling with children, or those who have playd in tree houses themselves as children, Hang Nga's Crazy House... will surely appeal.
Yeah, I've never played in tree houses. So that's my problem. But still this crazy house I found more interesting than Bao Dai's Summer Palace. Sorry to say. And yes, we were traveling with an 8 year boy, Gabriel.
Still from "Insight Guides Vietnam":
The never-completed house is continuously being added to, with tunnels, stairways and halls meandering into secret rooms and towers...
That's true. This book was printed in 2009 and when we visited Ha Nga's Crazy House in the very end of 2010, there were still parts being underconstruction.
About the architect, "Insight Guides Vietnam" says:
The architect, Dr Dang Viet Nga, daughter of the deceased General Secretary of the Communist Party in Vietnam, began construction of the fantasy house in 1990.
This crazy house also serves as a guest house which you can check out here and also find better photos than mine, of the entire house. However, my personal opinion is, if you are traveling with an elder and or, you have arthritis, you'd better not challenge yourself. Once again said "Insight Guides Vietnam":
The other rooms may be rented as accomodation, but guests may find the constant stream of visitors rather intrusive.
After all, following the mainstream is not always a crime. Everyone going to Dalat visits Ha Nga's Crazy House. So did I.