The United States, as one of the largest industrialized nations in the world, also has issues regarding infrastructural insufficiencies linked to climate change. Take a study of Las Vegas topology as an indicator. Research that created three Land use/land cover maps, or LULC maps, of Las Vegas in 1900 (albeit hypothetical), 1992, and 2006 found that "urbanization in Las Vegas produces a classic urban heat island (UHI) at night but a minor cooling trend during the day".[58] In addition to temperature changes in the city, "increased surface roughness" caused by the addition of skyscrapers/closely packed buildings in its own way were found "to have a mechanical effect of slowing down the climatological wind Windfield over the urban area".[58] Such unnatural environmental phenomena furthers the notion that urbanization has a role in determining local climate, although researchers acknowledge that more studies need to be conducted in the field.