Last week we wrote about "Megacities and the United States Army": a fascinating yet terrifying report in which the world's top military thinkers solemnly explain that they're going to have to invade somewhere really, really big one day.
The document didn’t just stun us with the essential OMFG-ness of its cheery vision of US tanks casually rolling into Lagos: it also contained a huge raft of interesting facts and figures about life and government in some the world's biggest cities.
Since we couldn’t find room for them in our original piece, we’ve put them here instead.
- Every day, the report says, an estimated 180,000 people migrate to cities. Scale that up, and you’ll discover it’s about 1.3m week. Or 5.4m a month. Or roughly the population of the UK every year. It's a lot.
- By 2030 60 per cent of urban dwellers will be under 18. This startling statistic highlights quite how much of the urban growth is coming in developing countries where life expectancy remains low.
- In 2011, four feet of rain hit Thailand in a single week, flooding an area the size of Kuwait. Many of Bangkok's eastern suburbs were under water for weeks. So were several major industrial estates and the runway at the city’s second airport, Don Mueang, which was closed for nearly five months. Egads.
A Thai woman paddles a makeshift raft through the Bangkok suburb of Rangsit, Novemer 2011. Image: Getty.
- Talking of flooding, sea-level rises will hit Bangladesh so badly that over, by 2030, Dhaka is expected to absorb 20m refugees. (The army at least believes in climate change.) Its current population is just 15m.
- Whether they'll have anywhere to live, though, is an open question: the Bangladesh Department of Disaster Management estimates that, in the event of an earthquake of 7.0 on the Richter scale, a minimum of 76,000 of the city's buildings would collapse. A minimum.
- Rio has 600 favelas (the Latin equivalent of slums). In November 2010 a riot that started in one of them led to city-wide violence; it took the intervention of over 3,000 police officers and military personnel to restore order.
- While we're on Brazil's less carnival-esque features, the First Command of the Capital is a drug gang that was formed in a Brazilian prison in 2001. By 2006 it was strong enough to co-ordinate 1,300 attacks across the city and launch riots in 73 different prisons, forcing the government to negotiate with it. "More disturbing than its emergence," the report says, "is the fact that a nation possessing the world’s eighth largest economy has been unable to uproot the gang despite building an enormous police force."
If you're wondering why the US army decided to work out how to invade and occupy a major city, this is as good a reason as any.