The Netherlands: Dutch children are the happiest in the world. Reyer Meeter is taking his kids on the daily school run, by bicycle.
In Amsterdam at 3pm, Benjamin, nine, is going for an impromptu swim with friends in the River Ij. There's no anxiety from his father Jan, 45, an urban planning consultant. ''Why should there be? He has his swimming diploma and he knows to stay away from shipping.''
Nor is there any need for Benjamin, a keen hockey player, to worry about homework. He doesn't get any.
China: Pupils start the day at 7am - by saluting the flag - and finish at 8.30pm, after three hours of supervised homework. Photo: Sanghee Liu
''Treats'' aren't reserved for after meals either. Many Dutch children start the day with hagelslag - bread topped with chocolate sprinkles.
When it comes to toys, board games like Ludo are still bestsellers, although the Dutch version, in honour of its infuriating nature, is called Mens Erger Je Niet! (Don't get worked up!).
A recent Unicef survey found Dutch children are the happiest in the world. Youngsters are treated as mini-adults - many 11-year-olds pick their own secondary school. Not that parents need worry. There are very few private schools, and all the state schools are decent. The same goes for universities - there's no Oxbridge elite.
United Kingdom: British children are among the most brand-conscious in the world. Photo: Kevin Coombs
''There's less pressure on children to succeed,'' says Paul Van Geert, a professor of developmental psychology. ''Parents see a happy childhood as very important.''
The pushy few, he reveals, send their children to school in Belgium.
Life at a glance
Life expectancy at birth: 80
Homework: None until the age of 10
Latest online game craze: Minecraft - players do battle with night-time monsters
Bestselling sweet: Drop - liquorice that can be sweet or intensely salty; a popular trick is to feed the latter to unsuspecting foreign guests
On a patch of waste ground under one of New Delhi's busiest railway bridges, Nishu, five, a vegetable seller's daughter, joins 50 children aged four to 15.
They put down their Angry Birds backpacks and fall silent for Rajesh Kumar, 42, a shop owner turned volunteer teacher.
The backpacks come from a donor touched by Mr Kumar's philanthropy. Nishu is one of 34 per cent of children who fail to finish primary school - she dropped out after the teacher beat her.
Her friends under the bridge tell similar stories about government schools where poorly trained teachers often turn up, write a problem on the blackboard and then leave. ''They just come and leave without answering any questions,'' says Bharat Mandal, 15.
Unlike Nishu, middle-class children are rarely seen on the streets, and then only accompanied by their ayah (nanny), who is included in the price of a family ticket at Indian museums.
In a country where space comes at a premium, however, many children sleep in the same room or bed as their parents until they're six or seven.
Meanwhile, among India's super-rich teenagers, motorbikes are the current craze, thanks to the wildly popular Stuntmania, an MTV show featuring ''street stunting'' motorbikes.
Life at a glance
Life expectancy at birth: 65
Percentage of five to 14-year-olds engaged in child labour: 12
Popular street game: Kite fighting - players paste their line with glue and finely powdered glass to try to cut the string holding their rival's kite
Obesity: Five out of 10 children in high-income families are obese
Monthly pocket money: 280 rupees (AU$4.77) for (middle-class) seven to14-year-olds, a rise of 200 per cent over the past decade
Democratic Republic of Congo (DRC)
In the DRC, children don't just have one mother. All Congolese women have the prefix ''Mama'' before their name, even if they don't have children.
Many ''mamas'' will help look after friends' or relatives' children or are employed as nannies or housekeepers by well-off families. Breast milk is shared too.
Children oblivious to the internet's charms love games like Bokwele - two teams draw a circle in the dust and place stones in the middle. The aim is to run and steal your opponents' stones without being touched by them.
Forty-two per cent of five to 14-year-olds, however, are engaged in child labour.
Kalala, 12, who likes singing and dancing, and who wears a faded T-shirt emblazoned with the image of a Harley-Davidson, was once one of them.
Although education is free and compulsory until 16, in practice, children are often required to earn money to help pay the teachers at chronically underfunded schools.
Kalala's father, a farmer, couldn't afford the subs so, aged five, Kalala had to work as a ''sifter'' at a diamond mine.
Children forced by poverty into begging and theft can expect little mercy. A 2009 law raising the age at which juveniles were treated as adults to 18 supposedly ensured no children went to adult jails. But it's been patchily enforced and 3,000 children are still in adult prisons.
''Every morning, you're forced to work,'' said Vincent, 16, who served time in a Kinshasa jail. ''If you don't, they beat you, pour water on you or lock you in a room.''
Life at a glance
Life expectancy at birth: 48
Average daily time on the internet: Zero
Children per thousand dying before their fifth birthday: 170
Abdulatef, an 11-year-old Arsenal supporter from Jeddah, likes computer games and going for camel rides on the beach.
He plays football on a pitch overlooked by a huge model of the Koran. He prays five times a day. When school ends, at 2.30, he's collected by the family chauffeur.
Most middle-class families have at least one servant - and many adolescents will acquire their own personal servant. Yet even privileged youngsters can't evade Saudi's infamous Sharia Law.
In 2010, a teenage girl who assaulted a teacher was sentenced to 80 lashes.
Teenage boys and girls are forbidden to meet - transgressors can be caned but more often get a verbal reprimand. To subvert the rules, ''numbering'' has become a rite of adolescent passage in urban Saudi Arabia. Gangs of young men in cars - wielding signs displaying their mobile numbers - chase vehicles with female passengers inside.
The web has made interaction easier but even virtual contact risks parental fury.
In 2008 a Riyadh father killed his daughter when he caught her talking to a man on Facebook - denounced by radical clerics as a ''gateway to lust''.
In Riyadh, 18-year-old Sara explains the complexities of getting to know the opposite sex: ''With the phone, everyone can agree that is forbidden, because Islam forbids a stranger to hear your voice. Online, he only sees your writing, so that's more open to interpretation.''
Life at a glance
Life expectancy at birth: 74
Number of brides under the age of 14: 5,622 - there's no minimum marriage age, but the government recently announced plans to set the limit at 16
Youth justice: Teenagers can be flogged and have limbs amputated
Bestselling chocolate bar: Galaxy
Last May, in the city of Nanjing, two teenage boys committed suicide - because they had failed to finish their holiday homework.
China's school system remains one of the most pressurised in the world. Pupils start the day at 7am - by saluting the flag - and finish at 8.30pm, after three hours of supervised homework. In the poverty-stricken countryside, meanwhile, children are often working the land rather than getting an education.
Jianhong, 14, from the city of Guilin, admits furtively taking out his mobile during ''boring English lessons'' so that he can ''instant message'' his friends. Back home, he'll battle them online. Until recently the craze was for the multiplayer QQ Farm - addicted teenagers would set night-time alarms to stop anyone stealing their virtual vegetables.
Now it's combat games like Dungeon and Fighter. Once, children had the occasional sip of alcohol at family parties. But recent news stories report shops selling alcohol to minors and teenagers feeling ''under pressure'' to get drunk.
Many say China's one-child policy has spawned a nation of over-indulged ''little emperors and empresses''.
One district nurse admitted spending a third of her monthly salary on miniature cars for her 16-year-old: ''I believe this can encourage him to put more efforts into his study, and I find it really works.''
Life at a glance
Life expectancy at birth: 73
School day: 80 hours per week (in cities), including Saturday mornings
Bestselling sweet: The ubiquitous White Rabbit Creamy Candy, a milk-based chew covered in sticky rice paper and once given to President Nixon on a state visit
Pocket money: Urban teenagers get up to 17 per cent of their families' monthly income, with an average allowance of 250 yuan (AU$44.23). Children in bigger cities, like Beijing or Shanghai, can receive up to 500 yuan (pounds 52)
Like all his friends at his Cambridgeshire primary school, Lewis, 10, was caught up in the craze for Trashies, the thumb-sized collectables that come with their own miniature dustbins and include such lovable characters as Boiled Brains and Putrid Pizza.
But when Lewis bought a ''trash pack'' for pounds 10 in February, he found it contained the 21st-century equivalent of a golden ticket: the ultra-rare Grimy Gold character.
He sold it on eBay for $1,000 (AU$1,700).
With a total of 7.3 billion pounds (AU$12.43 billion) worth of goods in their bedrooms, British children are among the most brand-conscious in the world.
Dr Tessa Livingstone, who created the BBC's Child of Our Time project, has noted that by four, most British children know which brands are which, and which celebrities wear what.
Toys have become status symbols over playthings. Other anxieties have become almost traditional: Britain's teenage pregnancy rate has long been the highest in western Europe; Britain's binge-drinking culture ensures only Danish children get drunk more often in western Europe.
The internet permeates almost every aspect of childhood - even Lewis's Trashies have their own online games.
British children, posting ''selfies'' on Facebook, and ''sexting'', using acronyms like YOLO (you only live once), seem to be living in a virtual world that's baffling and alarming many parents.
Meanwhile, a new generation of pushy parents, worried about standards in comprehensives or determined to get their offspring into selective schools, has started filling their children's lives with Saturday morning Mandarin classes, after-school Kumon maths and private tutors. ''Up here,'' said one north London mother, ''a tutor is a fashion accessory.''
Life at a glance
Life expectancy at birth: 80
Predicted Christmas bestseller: Furby Boom - a fully ''interactive'' version of the original furry robot pet is expected to take the top slot
Percentage of five to 11-year-olds given private tutoring over the summer holiday: 27 (56 at private school)
Youth justice: The age of criminal responsibility (10 in England and Wales) is the lowest in western Europe; rates of youth imprisonment are the highest
Annual spend on toys, per child: 270 pounds (AU$460), the highest in Europe
The Sunday Telegraph