Developmental records

The largest city by population is a notoriously hard record to track. First of all, municipal boundaries are often drawn differently in different countries with different purposes. While on one extreme the "City of London" is a tiny area with only a few thousand residents, on another extreme end of the scale, Chongqing, the largest city by official census counted population inside the administrative boundaries has about the surface area of Austria. Another difficulty is that large cities tend to attract immigrants from other parts of the country or even other countries and not all of them are officially counted by anybody - in fact, many of them do not even live in legally acknowledged dwellings. It is thus not uncommon to have different sources mention population figures for the same city that vary by several million people and there are few that even attempt to compare like with like.

Another approach to the population is counting the "metro area" or the population in an area roughly encompassing all areas of high population density around one or several urban cores and excluding the lower population density areas outside it. However, this has the obvious problem of defining where one draws the line, especially in regions of "urban sprawl" where one suburb bleeds over into the next with no clear boundaries evident anywhere. Additionally, not all residents of - say - Ruhr would like people going around pretending they all live in the same "urban area" or some such with the differences not mattering. Some geographers have even proposed "mega-regions" like "Bos-Wash" encompassing the Northeastern United States from Boston to Washington DC, and "Los-San" from Los Angeles to San Diego. The "Blue Banana" in Europe encompassing everything from the Benelux North Sea Coast, down the Rhine to Northern Italy is rarely seen as a coherent agglomeration or urban area but has been proposed as the likes of "Bos-Wash".

The same goes for the "oldest city". 🌍 Damascus is sometimes cited as the oldest continuously inhabited city. Damascus itself was founded about 3000 BC, but people lived in the area already at 9000 BC. Also elsewhere in the Middle East there's archaeological evidence of cities/towns from around 9000 BC. Another candidate is 🌍 Argos, which may have been continuously inhabited since the 6th millennium BC. The definition of just what constitutes a "city" is also difficult, but sometimes "has a wall surrounding all or most dwellings" is used as a proxy. Of course modern day cities usually do not have a town wall.

At some 5,100 m (16,700 ft) above sea level, 🌍 La Rinconada is the highest city in the world with permanent settlement. The lowest is 🌍 Jericho, 258 m (846 ft) below sea level, and with archaeological founds from around 10000 BC, it's also among the oldest cities in the world.

The city of 🌍 Auckland in New Zealand is by some measures the world's most isolated city with a population of at least 1 million; the next nearest city with a population of at least 1 million is Sydney, 2,160 km away across the sea in Australia. Another claimant to this title is 🌍 Perth, which is 2,131 km from Adelaide, the nearest city with over 1 million inhabitants, across the vast and remote Nullarbor Plain. For most visitors, Perth feels more isolated than Auckland as there are numerous cities with populations of over 100,000 within a day's drive of Auckland, while there are none close to Perth or anywhere else in Western Australia for that matter, as Adelaide is the nearest city with a population of over 100,000.

If we lower the population threshold to 100,000, then 🌍 Honolulu in Hawaii becomes the world's most isolated city; the closest city with a population of over 100,000 is either Daly City (if using the city hall) or its neighbor of San Francisco (if using the closest land point) across the Pacific Ocean in California, 3,850 km away. Some other honourable mentions include 🌍 Anchorage, Alaska, 2,136 km from Vancouver in British Columbia, Canada, 🌍 Reykjavik, Iceland, 1,325 km away from Aberdeen, Scotland, and 🌍 Petropavlovsk-Kamchatsky, Russia, 1,321 km away from Yuzhno-Sakhalinsk.

The most isolated human settlement in the world according to the Guinness Book of Records is 🌍 Edinburgh of the Seven Seas on the island of Tristan da Cunha, a British overseas territory; the next closest human settlement is the island of Saint Helena 2,161 km away. With less than 300 inhabitants, it is so remote that it does not have an airport, and the only way to get there is a 1-week-long boat ride from Cape Town, South Africa.

Main article: Architecture#Tallest buildings

• 🌍 Burj Khalifa in Dubai is, with a height of 829.8 m (2,722 ft), the tallest building in the world. The building also holds other height records including the world's highest elevator, observation deck, restaurant and nightclub.

What's considered the "oldest building in the world" depends on what one considers a building and in which state it is nowadays. One candidate for the title would be the 🌍 Barnerez mound, a burial mound from around 4800 BC and still standing. The temple of 🌍 Göbekli Tepe outside Urfa has been dated to the 10th millennium BC, and was abandoned in the 8th millennium BC (today it's a world heritage-listed archaeological site). The oldest discovered structure with human impact is a rock covering the entrance of the 🌍 Theopetra cave, possibly placed there as protection against the wind.

• The Trans Siberian Railway from Moscow to Vladivostok is the longest railway in the world. In addition to regular service along its entire length there is a once-weekly through carriage from Moscow to Pyongyang which while not easy to book for holders of most passports is the longest possible scheduled train journey one can take without leaving the carriage once. The longest possible train journey with multiple changes but with the condition of all train transport would begin somewhere in Iberia and end somewhere in Southeast Asia; see Portugal to Singapore by train for a version.

Glasgow subway has some of the lowest clearance subway rolling stock for passengers. Parry people movers are the shortest length passenger carriages on heavy rail track. Glacier Express is said to be the slowest average speed 'express' train.

The world's longest highway is the Australian Highway 1, a 14,500-km (9,000-mi) ring road around the whole country.

• The rather short 1.4-kilometre 🌍 Chandler Highway in Melbourne is said to be the world's shortest highway

• The Beijing-Shanghai high speed railway features three of the world's four longest bridges, all of them viaducts. The longest in the world, the 164.8-kilometre (102.4 mi) long 🌍 Danyang-Kunshan Grand Bridge is one of them.
• The longest road bridge, also a viaduct, is the 🌍 Bang Na Expressway (officially Burapha Withi Expressway) in Thailand, a 55-km (34-mile) long elevated highway running from the Bang Na district of Bangkok to Bank Pakong district in Chachoengsao province.
• The longest continuous bridge over water, also a viaduct, is the 🌍 Lake Pontchartrain Causeway in the US state of Louisiana, consisting of two parallel bridges that cross the New Orleans-area estuary for nearly 24 miles (38.4 km) from the south shore suburb of Metairie to the north shore suburb of Mandeville.
• The bridge with the longest main span, also the longest suspension bridge, is the 🌍 1915 Çanakkale Bridge that carries highway traffic across the Dardanelles strait in Turkey near the city of Çanakkale. Its main span is 2,023 m (6,637 ft).

Due in large part to the problems with exhaust, virtually all tunnels beyond a certain length are intended for electric trains only. Urban rail tunnels such as Berlin U-Bahn's all tunnel U7 were the longest tunnels for a long time, however, due to some of them being constructed via "cut and cover" (i.e. the would-be tunnel is built as a trench and later covered with a "roof") some argue those don't count. It is also sometimes difficult to assess whether two connected tunnels count as the same tunnel for length purposes. As of early 2019, the main contenders - largely depending on your definition of the word "tunnel" - for longest tunnel were the Gotthard Base Tunnel and the Guangzhou Metro Line 3. Various water pipelines are longer than those two but aren't usually what people think about when they hear "tunnel". At any rate, in the late 2010s there were no structures under construction that could rival the claim of either.

As for undersea tunnels, there are two claimants, depending whether you measure by total length by "longest underwater portion". The two claimants are the Channel Tunnel and the Seikan Tunnel in Japan.

The longest tunnel under a mountain or massive is the Gotthard Base Tunnel in Switzerland.

As the climate gets harsher and harsher towards the poles, population density and signs of civilization peter out the farther north one goes. While the Nordic countries benefit from the Gulf Stream and allow relatively traditional forms of human sustenance at pretty high latitudes, Northern Canada, the Russian Far North or Arctic Alaska do not have that benefit and besides nomadic hunter gatherer cultures human habitation is largely limited to resource extraction and military activity with a few scientific endeavors taking place at high northern latitudes. In the South the situation is a bit different as Antarctica as a whole wasn't even seen by human eyes until the 19th century and after the "race to the Pole" was won it was ultimately decided to turn Antarctica into a "common heritage of all mankind" with severe limitations on military use and resource extraction. As such, much of the activity in Antarctica is of a scientific nature.

The problem here once again is one of definitions. While there are definitions of "settlement" that count any single hut or house intended for human habitation and occupied regularly by at least one human as "settlements", there are other definitions that don't count purely military or research installations. In addition to that, Canada and to a lesser extent Denmark/Greenland (in the North) as well as Argentina and Chile (in Antarctica and the southern parts of South America) have created "settlements" and induced people to move to remote places in high latitudes just to stake some sort of political claim. Regular human sustenance off of agriculture, fishery or any other activity usually associated with human settlements is not possible at many of those sites and as such they are largely dependent on the government bringing in goods and maintaining services for political reasons. Some otherwise military installations also have a "civilian settlement" attached as a fig leaf. As such, some claimants for "northernmost settlement" in particular are called into question by those pointing out their nature.

• The northernmost settlement is a small community called 🌍 Alert, which is on Ellesmere Island. The town's population is so small, however, that it can be hardly even called a settlement. The purpose of Alert is purely military and its entire population is connected to military activities. 🌍 Ny Ålesund on Svalbard while being a company town claims the title of northernmost civilian settlement.
• The southernmost settlements are the Antarctic bases, which exist on the continent Antarctica. The southernmost of these is the 🌍 Amundsen-Scott Base, which is just a short walk from the South Pole. Argentina and Chile claim one of their bases each to be "civilian settlements", namely 🌍 Villa las Estrellas (Chile) and 🌍 Esperanza Base (Argentina). It was here that the only recorded births on Antarctica occurred. Esperanza Base also maintains a school, the southernmost on earth. 🌍 McMurdo Station while not claimed to be a civilian settlement is the only place in Antarctica and thus the southernmost place in the world capable of holding more than a thousand residents, which it does each Austral summer. 🌍 Puerto Williams, in Chilean Patagonia, is the world's southernmost settlement outside of Antarctica, and the southernmost undisputedly civilian settlement.

The southernmost capital of a UN member state is 🌍 Wellington, New Zealand and the northernmost is 🌍 Reykjavík, Iceland. However, 🌍 Nuuk, the capital of Greenland is further north than Reykjavík, while 🌍 Stanley, the capital of the Falkland Islands, is further south than Wellington. While Greenland is not a member of the UN, it has rather strong autonomy within the Kingdom of Denmark. The Falkland Islands are a British overseas territory that has considerable autonomy in governing its internal affairs, with Britain only responsible for foreign affairs and defence. They are also claimed by Argentina, and were the subject of a war between the two countries in 1982. Even further south than Stanley is 🌍 King Edward Point, the capital of South Georgia and the South Sandwich Islands, another British overseas territory. However, unlike the Falkland Islands, it does not have any permanent inhabitants, and is only home to a small transient population of scientists and British government employees.

• The Helsinki metro is the northernmost in the world. Its northernmost stop is 🌍 Mellunmäki.
• The Melbourne metro when it opens in 2025 is to become the southernmost metro in the world. Until then, the southernmost system is the Subte of Buenos Aires, the southernmost stop being 🌍 Plaza de los Virreyes - Eva Perón.

• The southernmost railway of any gauge and purpose is the 500 mm gauge 🌍 Southern Fuegan Railway which runs all of 7 km (4.3 mi) from Ushuaia to the Tierra del Fuego National Park initially built to transport timber for a local prison it was decommissioned in the 1950s and reopened in 1994 as a tourist railway. As it doesn't connect to any other part of the rail network and its steam drawn trains keep to a leisurely pace, its value is mostly as a tourist attraction.
• The northernmost railway of any gauge and purpose is the Obskaya–Bovanenkovo Line built to 1520 mm Russian gauge. This line opened in 2010 and was built by Gazprom primarily for freight purposes. It thus beat the Kirkenes–Bjørnevatn Line also mostly a mining line, built to standard (1435 mm) gauge. This line's electric infrastructure was destroyed in World War II. Thus the northernmost electrified standard gauge railway, also reaching the northernmost point reachable by rail travel in Europe on a standard gauge line is the Iron Ore Line or Malmbanan which together with some branches connects Luleå to Narvik, a major iron ore deposit and mine to one of the northernmost ice free ports. While its purpose is indeed mainly freight, there are regular passenger services bookable just like any other Swedish train. Narvik is not connected directly to the rest of the Norwegian rail network. You can get slightly further north by electrified passenger train, albeit along Russian gauge tracks by taking the train to Murmansk; further north(west) to Nikel is nowadays for freight only.
• The Qinghai–Tibet railway reaching an altitude of 5,068 m (16,627 ft) reaches the highest point that can be reached by any railway of any type gauge and purpose.

• Of routes that operate as roads, the highest road is probably the road from Demchok in India to Umling La in Tibet (China). The elevation at the highest point on this road is 5,800 m (19,029 feet).

Again the question of definitions enters the picture here. There is, for example, a seasonal ice landing strip during the austral summer serving the Amundsen Scott South Pole Base which allows specially equipped planes to briefly touch down, be unloaded with their engines running and take off again, but most people wouldn't call this an airport in the traditional sense. The only place in Antarctica with an IATA code is TNM ^IATA. The world's highest airport is Daocheng Yading Airport (DCY ^IATA) in Sichuan, China at 4,411 m (14,472 ft) above sea level, while the world's lowest airfield at 378 m (1,240 ft) below sea level is Bar Yehuda Airfield (MTZ ^IATA) in Israel near the Dead Sea.

The northernmost university is the 🌍 University of Tromsø in the Norwegian city of that name. The southernmost is the 🌍 National University of Tierra del Fuego in Ushuaia, Argentina.