Mauritania is a vast Saharan wasteland of more than a million square kilometres (400, 000 square miles).
But since a great collapse in 2007 the figure has been closer to 4.3m square kilometres.
In Colombia drought has parched 5, 000 square kilometres of pasture and 2, 000 of maize, sorghum and soya.
These sprawling compounds consist of buildings and underground bunkers that cover some 12 square miles (30 square kilometres).
Two years ago, its 40, 000 square kilometres (15, 400 square miles) were officially reckoned to include five square kilometres of coca plantations.
Covering 5268 square kilometres and including 45, 000 dwellings, the Biosphere provides an unpunctuated skyline across much of its expanse: the ideal conditions for stargazing.
The 3, 500 residents who remain are crammed into emergency housing on the 16 square miles (40 square kilometres) still judged safe.
And what if that tiny population is scattered across 30, 000 square kilometres (11, 000 square miles), only 1% of which is above water?
Covering 5268 square kilometres the Galloway and Southern Ayrshire Biosphere was granted its status in recognition of the special natural qualities that characterise the area.
By September the ice regularly used to melt to 7m square kilometres.
The first Polynesian voyagers used indigenous scientific astronomical knowledge, harnessing the night sky and the environment to guide them across 162 million square kilometres of ocean.
The site, which counts some 15 villages within its 42 square kilometres, is also threatened by pressures on land use for development and tourism.
The discovery is more like damp rock: a mixture of 1% ice and 99% regolith, spread over thousands of square kilometres at the poles.
ECONOMIST: At least lunar gold-diggers will be able to take a shower
SKA's proponents are talking of scattering its sub-telescopes over an area of 1m square kilometres, which would create an effective diameter of about 1, 000km.
It covers an area of 11, 437 square kilometres (4, 575 square miles).
They have made Hilton Head, a few of whose 42 square miles (109 square kilometres) are still undeveloped, an even more attractive place to live.
In the next 20 years, the report says, Britain is likely to lose at least 13, 000 hectares (130 square kilometres) of saltmarsh, mudflats and coastal lagoons.
BBC: By BBC News Online Environment Correspondent Alex Kirby
Until June the government in Tokyo took radiation measurements at just one site, as if that were enough to survey the city's 2, 200 square kilometres and 13m people.
Urban areas in the UK cover around 16, 000 square kilometres.
Beaverhead County, Montana, covers 5, 600 square miles (14, 400 square kilometres).
More than 50 companies exploring geothermal projects in Australia have taken out over 400 licences for areas covering nearly 500, 000 square kilometres a combined area roughly the size of Spain.
So, to make it habitable, 2, 330 square kilometres of sheep grazing territory were cleared out before American Walter Burley Griffin stepped in to design the new geometrically exact city.
BBC: SPORT | Rugby Union | Rugby World Cup | Venues Guide | City guide: Canberra
At the end of the winter, the frozen seas cover 15.7m square kilometres (6.1m square miles), an area more than one and a half times that of the United States.
The Antarctic ozone hole's current size is approximately 10 million square miles (26 million square kilometres.) It is approximately three times the area of Australia and is the largest ozone hole ever.
Despite being a commercial forest that is sustainably logged for wood, the Dermakot Forest Reserve in Sabah, which is an area of approximately 550km square kilometres, holds all five wild Bornean cat species.
BBC: Earth News - Clouded leopard: First film of new Asia big cat species
Apophis is some 350 metres across, considerably larger than the object that is thought to have flattened 2, 000 square kilometres of Siberian forest as it vaporised in the atmosphere above Tunguska in 1908.
The Inner City covers an area of 2.99 square kilometres (1.15 square miles) and the outer walls surrounding the city east and west of the Euphrates enclose an area of 9.56 square kilometres (3.69 square miles).
French Polynesia is made up of some 200 islands -- the Society, Tuamotu, Gambier, Austral and Marquesas groups -- spread over 4.1 million square kilometres of Pacific Ocean: an area roughly eight times the size of France.
Its breezy cosmopolitan capital, Papeete, sits on Tahiti's northeastern tip and is the gateway to a captivating world of indigenous culture that infuses a chain of islands spread across 5 million square kilometres of sparkling ocean between Australia and South America.
Brigadier Gordon Messenger, a spokesman for the British military, conceded on the Today programme that the security zone in the Sangin valley is just "several square kilometres" in size but added that this provides a haven for the local population.
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