We all know people who can effortlessly reel off the capital cities of countries we’ve barely heard of. Trying to catch out these trivia buffs is futile. They know their Dominican Republics from their Dominicas and you’re unlikely to bamboozle them by asking about Guinea, Equatorial Guinea and Guinea Bissau. Or even Papua New Guinea. YouTube is awash with cute kids reciting their ABCs (Athens, Bangkok, Cairo, etc), although the flawless performance of two-year-old Arina on a live television show, while impressive, does suggest that tiger parenting is alive and well in Ukraine. So just how much do you know about Hong Kong? Take our quick test Experts in this specialised field add extra layers of knowledge. They announce (to anyone who hasn’t managed to run away quickly enough) that Bangui, in the Central African Republic, lies on the Ubangi River, making it the only capital located on a river whose name is an anagram of its own. They’ll casually drop into conversation that Beijing is unique among first cities for having three consecutive dotted letters and that Thimphu, in Bhutan, is the world’s only capital without traffic lights. Still awake? There’s more. 1 Least Polluted Let’s begin with the jealousy-inducing news that Stockholm and Wellington are jointly rated the world’s least polluted capital cities by the World Health Organisation. The Scandinavian city has cut carbon emissions by 25 per cent since 1990 by introducing recycling programmes, improving public transport and promoting cycling, but there are clouds on the horizon. Stockholm’s vibrant, glorious public spaces are a riot of colour and culture A WWF Living Planet Report criticises Sweden’s unsustainable addiction to consumer goods, produced using fossil fuels in countries such as China. Coincidentally, Beijing is the world’s most polluted capital (bet it would rather be known for those three successive dots). The explanation for Wellington’s untainted air, meanwhile, is clear. 2 Windiest Along with back garden badminton, pollution doesn’t stand a chance in New Zealand’s blustery capital. Forget Chicago, the real Windy City is Wellington, where average speeds are 11km/h higher than its breezy American rival. The Kiwi capital lies in the path of a strong westerly airstream known as the Roaring Forties, which howls through the Cook Strait, pummelling pedestrians and keeping toupee wearers on their toes. New Zealand’s hiking trails offer a catalogue of wonders Wellington is also the world’s southernmost capital city, if we discount Port Stanley, in the Falkland Islands, which is an overseas territory rather than a sovereign state. 3 Northernmost The “is it or isn’t it a proper country” debate applies at the top of the planet as well. Reykjavik huddles up against the Arctic Circle, meaning that in December, the Icelandic capital experiences about four hours of daylight, although it seems less when it’s raining or snowing – which it usually is. Where to find and how to photograph the Northern Lights On the upside, December is a good time to witness the spectacular and surreal Northern Lights. The natural phenomenon can also be seen in Nuuk, a city of 17,000 shivering souls (average July temperature, eight degrees Celsius), which will replace Reykjavik as the world’s northernmost capital just as soon as Greenland completes the process of securing full independence from Denmark. However, these North Atlantic neighbours aren’t the worst when it comes to the risk of frostbite. 4 Coldest While there are colder places on Earth (the average winter temperature in the Russian city of Yakutsk is minus 34 degrees Celsius), Ulan Bator is the world’s coldest capital. Long periods of nose-numbing temperatures mean Mongolians are more likely to be in favour of global warming than the rest of us. Herders’ incomes are threatened by livestock deaths; pollution soars as anything and everything (tyres, old shoes) is lobbed into the stove for warmth; and if a family member dies, relatives need to keep a fire burning to melt frozen ground to dig a grave. Deadly winters, climate change spell doom for Mongolian herders The relentlessly frigid weather does at least create opportunities for Mongolian copywriters. “Winter Time is Pepsi Time” wins the prize for shrewdest marketing ploy in a country where the mercury rarely climbs above zero for months on end. 5 Hottest With an annual average of 28 degrees Celsius, Bangkok is the world’s hottest capital city. After a few “chilly” days in December, temperatures rise relentlessly through January and February and by Thai New Year, in April, they have reached levels that would melt a Mongolian. Bangkok – the good, bad and ugly sides to the Thai capital for visitors The Songkran water festival is a brief opportunity to cool down before the heat intensifies in the run- up to the rainy season. Pollution and humidity add to the feeling of discomfort, with little respite at night. A shortage of green space to absorb the urban heat doesn’t help, nor does the overuse of air conditioners, cars and concrete. Sound familiar? 6 Highest Ear-popping La Paz is so far above sea level that airline passengers may notice a drop in pressure when the aircraft doors are opened on arrival. At 3,650 metres, symptoms of altitude sickness are as common for tourists walking the streets of the Bolivian city as they are for mountaineers high in the Himalayas. In 2007, Fifa decided that playing home matches in the world’s highest capital gave the national soccer team an unfair advantage. Opponents complained they didn’t have enough time to fully acclimatise and Bolivia were banned from hosting competitive fixtures in La Paz. Vision in white Chewing coca leaves or drinking coca tea (both legal) helps to alleviate feelings of nausea and throbbing headaches, but if you’re worried that a trip to the Andes might leave you breathless, consider instead a visit to Baku, in Azerbaijan, which at 28 metres below sea level, is the world’s lowest lying capital. 7 Oldest and Youngest Damascus is generally accepted to be the world’s oldest continuously inhabited city. Chosen as the capital of the Umayyad Caliphate in AD661, there’s evidence of habitation dating back more than 11,000 years. The war-torn Syrian cradle of civilisation, nominated as Arab Capital of Culture in 2008, was, unsurprisingly, ranked the least liveable city in 2017. Coincidentally, the world’s youngest capital, Juba, in South Sudan, is one of the most dangerous places in the world. Aid workers have been shot at, ambushed, violently assaulted and robbed. The US State Department warns its citizens to have evacuation plans that do not rely on US government help.