Construction has advanced greatly in the last one hundred to two hundred years and has created many records in development. Developmental records are often fascinating points of interest or tourist attractions in their respective cities and many countries try to build the tallest buildings or longest bridges to show off their country's successes.
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 geographs have even proposed "mega-regions" like "Bos-Wash" encompassing the Northeastern United States from Boston to Washington DC, "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 millenium 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 above sea level, La Rinconada 📍 is the highest city in the world with permanent settlement. The lowest is Jericho 📍, 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
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 millenium BC, and was abandoned in the 8th millenium 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.
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.
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 southernmost capital of a UN member state is Wellington, New Zealand and the northernmost is Reykjavík, Iceland. However, Nuuk, the capital of Greenland is farther north than Reykjavik. While Greenland is not a member of the UN, it has rather strong autonomy within the Kingdom of Denmark.
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 IATA: TNM. The world's highest airport is Daocheng Yading Airport (IATA: DCY) in Sichuan, China at above sea level, while the world's lowest airfield at below sea level is Bar Yehuda Airfield (IATA: MTZ) 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.