Els Castells ja són Patrimoni Cultural i Immaterial de la Humanitat. This is by no means immaterial: UNESCO has declared Catalonia's castells part of the "Intangible Cultural Heritage of Humanity."

Castells are not just a bunch of Catalans standing on one another's shoulders in what UNESCO boringly translates as "Human Towers." They're collective, athletic performance art. They take years of practice and minutes to build.

And while UNESCO says they are a way to fend off the culture-eroding power of globalization, they are essentially done for kicks. What got them on humanity's heritage list, among other things, is that they are traditional, passed down through generations, yet "living"; they're part of a particular cultural identity, yet inclusive.

UNESCO doesn't mention it, but what Ed thinks is especially amazing about castells is the important role children play in their making.
They're moving to watch, even if you're not a Catalan: http://www.youtube.com/watch?v=-iSHfrmGdyo&feature=player_embedded