Power of tower

October 4, 2016 6:49 AM

Building human towers in Spain - Every year in Spain, a Catalan tradition of building Castells—human towers reaching up to 10 stories—takes place.

Teams called colles compete to build the tallest and most complex tower made only of human beings standing atop one another. Teams are considered to have been successful if they can build and deconstruct their towers without a fall.

posted by a lungful of dragon (24 comments total)

In the hills, the cities
posted by filthy light thief at 6:57 AM on October 4, 2016 [21 favorites]

Incredible. I was just thinking that sometimes crowd stampedes happen and lots of people die but it's not because of the high density low space ratio, but simply because of panic and lack of knowledge about how to behave in a moving crowd. Maybe there are lessons to be learned for people who arrange major events, like hajj where deadly stampedes frequently happen.
posted by Foci for Analysis at 7:03 AM on October 4, 2016 [1 favorite]

Two days ago we had in the newspapers that the Xiquets de Hangzhou, a colla from China, have done a nine-story tower in a contest in Tarragona. English language writeup here.
posted by sukeban at 7:06 AM on October 4, 2016

(Els Xiquets de Hangzhou are mentioned in passing in the original link, but their awesomeness deserves better!)
posted by sukeban at 7:09 AM on October 4, 2016

Thanks for the extra links, sukeban!
posted by a lungful of dragon at 7:16 AM on October 4, 2016

Any engineers reading this one? It looks to me like the bottom level is pushing inwards, providing stability, and the second level is doing some of that too, but the upper levels go straight up, with maybe 4 people at each level. So, someone on level three has 2-4 people above them, weight coming straight down. That's...a lot of weight on your shoulders. Barefoot ftw.

The design looks perfected -- every tower team looks basically the same -- but there'd be differences in how much they practiced, how well they assess which level a person should be in, etc (like, how well do they handle a collapse): interesting find, and beautiful pictures!
posted by Mogur at 7:28 AM on October 4, 2016

Some metafite experience in my previously.
posted by Mitheral at 7:48 AM on October 4, 2016 [1 favorite]

It looks to me like the bottom level is pushing inwards, providing stability, and the second level is doing some of that too, but the upper levels go straight up, with maybe 4 people at each level.

Emphasis mine.

Well, yea. That's the way forces work in situations like this. You'd much rather put too much force towards the interior of the pile than have a lapse and let yourself be pushed outwards. I did a bit of work with Dr. Beth Todd at UA and her insights into how biomechanics work in practical applications are pretty interesting.

But, without going too far into the rabbit hole, it's a basic physics problem. It all relies upon people's shoes and their ankles, at least insofar as I read it. That is to say the coefficient of static friction, the area of their shoes, and their mass combined (in a complex way) with how much torque their ankle muscles can deliver whilst still remaining within the bounds of human physiology.

Let's say you're on the outside of the bottom row of the pile. You decide, because reasons, to not push inward. That means you're not exerting force into the pile anymore. Assuming someone isn't directly above you (you're one the outside of the pile, so this assumption is probably fairly safe/valid) then you're contribution is now nil, whereas if you were pushing towards the interior, you're doing your part, again as I see it, in one way and one way only: making sure someone else can push towards the inside or, as you get to the people actually supporting another tier, locking a human body that is carrying weight into the upright position.

That human that is carrying weight can support more than his/her legs could normally carry because now you have an amount of force related the the static friction of all the other humans pressing against them from the sides. Not to mention that their stabilizing muscles of the folks in the lower tiers are now far less crucial, unlike the trained gymnasts you might find in a circus tightrope situation or something. Those folks you put up top. And children, tiny, tiny children.

RoE's TL;DR - human pyramid materials (aka humans) are only strong in compression, not at all in horizontal tension.
posted by RolandOfEld at 8:19 AM on October 4, 2016 [6 favorites]

This was featured recently in the BBC series "Forces of Nature" with Brian Cox. There's an edited version of that part of the programme on YouTube. Includes some heartstopping moments when the towers collapse.
posted by Stark at 8:47 AM on October 4, 2016 [1 favorite]

So glad to see women participating on all the teams as if it's no big deal.
posted by jfwlucy at 9:47 AM on October 4, 2016

Being born in Barcelona city I always considered castells something folkloric, I didn't dislike it but never interested me. Then I moved to the countryside, to el Penedès, home of one of the best colles, if not the best: els castellers de Vilafranca, o els verds (the green ones). And then I went to the plaça de la vila (town's main square) to see them perform. One thing is to watch it in TV, but when you are there you realize what it takes to build those inmense human towers, the huge amount of people and how they arrange themselves, stronger, thicker people at the base and the higher they go the smaller they are, until the very last to climb, the enxaneta, could be a 5 five years old girl! Being there you can feel the tension, the excitement of the crowd, how silence is made just before the sound of the gralla (catalan version of a shawm), when the final floors of the tower are being built. You feel part of them.

Quick anecdote: when I have special visitors, and after having a nice dinner in a nearby restaurant, I show them how the Castellers de Vilafranca train, anyone can walk in! And one day, while we were watching them building a tower, the cap de colla (like their coach) approached us, took my friend and I by the hand and put us in the outer part of the tower base! We did very little, just push and "hug" the guy in front of us, but then we felt definitely part of the colla.
posted by samelborp at 12:20 PM on October 4, 2016 [18 favorites]

An amazing living symbol of community solidarity.
posted by bertran at 3:06 PM on October 4, 2016 [2 favorites]

Great photos! But they're even more amazing when you can see the incredible coordination it takes to build them and take them down. The Catalan television program "Quarts de Nou" covers the Castellers every week as though it were a major sporting event. Check out the videos here to see what the competition featured in these photos looks like in motion. You can skip the 3-minute summary at the top of the page; the videos further down really give you an idea of how difficult and beautiful this is.

I was in Barcelona the other weekend for the Mercé. It's the first time I've gone to see the castellers in a few years, and it's amazing how the competition has intensified since the last time I saw them. An 8-level castell was impressive a few years back; this time I got to see two successful 10-level towers.

One really encouraging sight was the number of nonwhite people participating who were probably children of immigrants. It gives me hope that Catalonia will not go down the same path as France, and instead find a way to make the second generation feel genuinely integrated into Catalan society.
posted by fuzz at 4:26 PM on October 4, 2016 [4 favorites]

This is so impressive and interesting. That first floor of compressed people where I'm amazed anyone in the centre can still breathe, but which is all to support the individuals who still have the weight of an entire side of the tower on their shoulders alone. The way it looks so solid from afar, but you can see everyone shaking with exertion and reacting to every shift on close up.

There's a little bit of detail on wikipedia about the types of tower pattern, the specifics of the rows and the top pair of children, but I'd love to read some more nitty gritty if there's anything available in English.

The raucous support for the Chinese team makes me happy too.
posted by lucidium at 5:14 PM on October 4, 2016

Is this next level single person tower a recognised thing or an extra bit of showmanship?
posted by lucidium at 5:33 PM on October 4, 2016 [3 favorites]

These pics are amazing, what a cool thing.
posted by LobsterMitten at 9:57 PM on October 4, 2016 [1 favorite]

The festival I went to got rained out—so I just randomly dropped by where the Castellers de Barcelona practice. You can just hang around outside a gym with a half-dozen other spectators, drinking your €1.50 beer, and watching normal-looking people casually making one eight-story tower after another. A+++, would go again.
posted by vasi at 11:53 PM on October 4, 2016 [1 favorite]

Is this next level single person tower a recognised thing or an extra bit of showmanship?
It's a recognized thing: a 3 de 9 amb folre i l'agulla. The folre is the second level of people supporting the tower, and the agulla (literally "needle") is the pillar in the middle. It seems incredibly difficult and I've only seen it done live a couple of times.
posted by fuzz at 2:22 AM on October 5, 2016 [3 favorites]

I live a couple of blocks from Plaza Jaume in Barcelona, they have castellers there on holidays and festival days, that kind of thing. I'm always amazed by how few people there are watching. I mean, the streets are full and I guess there's 1000 or so people watching, but it's such an amazing thing to me, one would think that it would be a spectacle on par with La Tomatina or the running of the bulls. I consistently get a lump in my throat from watching, I don't know why but it seems to soeak to something primal in me. Same for anyone else?
posted by conifer at 8:08 AM on October 5, 2016 [2 favorites]

Human beings are fucking incredible sometimes.
posted by penduluum at 9:51 AM on October 5, 2016 [2 favorites]

Conifer, I got a little teary watching the videos. For me maybe something about seeing humans using absolute max effort and concentration and practice and will towards something so interesting and cooperative and doing it for reasons that are not war, not politics, not anything to do with the ugly in humans.

Thanks so much for posting this and sharing experiences about it. I never would have known and it's awesome!
posted by eggkeeper at 2:09 PM on October 9, 2016

It's also show of strength and agility that is not hyper-masculine and is mixed gender and mixed age. I love it.
posted by deadwax at 8:09 PM on October 9, 2016

I was in Barcelona last year during La Mercè, and watching castellers was one of the highlights.

So glad to see women participating on all the teams as if it's no big deal.

I think this is characteristic of women in Catalan society in general, from the (admittedly short) time I was there.

Back to castellers, the top-most person ("enxaneta") is usually a small girl, who has climbed all the way to the top of the human tower many stories above the cobblestone plaza. It is crazy brave. If and when she gets to the top, she does a defiant "clawing" gesture symbolic of Catatonia independence / separatism (and the red stripes on their flag, which themselves symbolize a Catalan hero of legend dragging his bloodied fingers down a yellow Aragon flag in defiance).

I consistently get a lump in my throat from watching, I don't know why but it seems to soeak to something primal in me. Same for anyone else?

Definitely. I found the castgeller exhibition during La Mercè thrilling and moving and I too found myself choked up with emotion. Hell, I am getting a little teary just typing this comment thinking back on it.
posted by aught at 8:01 AM on October 28, 2016 [2 favorites]

and the red stripes on their flag, which themselves symbolize a Catalan hero of legend dragging his bloodied fingers down a yellow Aragon flag in defiance

Going a bit offtopic, but the legend of Guifré el Pilós and the shield is totally ahistorical and a 19thC invention, and the red bars on gold were the senyal real of the Crown of Aragon.
posted by sukeban at 1:51 AM on October 31, 2016