I come to this forum to explain you that human castles are not dangerous.
This is a tradition of Catalonia (North-East of Iberian peninsula). We don't like bullfighting and most of us have never taken part in a Tomatoes War.
The aim of human castles is to build up the highest and most difficult castle that each group can. In order to improve, each group has 1 to 3 trainings per week, and each part of the castle is tested in advance, so every one of us knows exactly what to do and how.
As we allways try to do it more and more difficult, we can't avoid fallings, but although they may look "nasty", they aren't at all. The people under the castle is there to hold the weight and the possible falling of the castle.
Last year 56 groups were active and 6556 human castles were tried, of which only 616 fell down (less than 4%). Accident rates (comparing damage to practising time) are similar or even lower than those of other sports, such as football. All castle builders are protected by an insurance.
Human castles have been built in Catalonia for almost 200 years and only 3 or 4 deaths have occurred in this time span.
When I was a child, I used to climb up to the top, I fell down more than 20 times and I am proud I never panicked down. Now I am usually under the castle and some castles fall on us, you just get a bump. If I ever have children, I will teach them how to climb.
If you have questions on this subject, please ask me. You can see fotos and find more information at:
www.collajove.com
But best of it is come on holidays to Catalonia (Salou, Barcelona, Girona, etc.) and see it live!