45th parallel north in the context of "December solstice"

The Po (/poʊ/ POH, Italian: [ˈpɔ]) is the longest river in Italy. It flows eastward across northern Italy, starting from the Cottian Alps. The river's length is 652 km (405 mi), or 682 km (424 mi) if the Maira, a right bank tributary, is included. The headwaters of the Po are formed by a spring seeping from a stony hillside at Pian del Re, a flat place at the head of the Val Po under the northwest face of Monviso. The Po then extends along the 45th parallel north before ending at a delta projecting into the Adriatic Sea near Venice.

Draining a basin of 74,000 km (29,000 sq mi), the Po is characterized by its large discharge (several rivers over 1,000 km have a discharge inferior or equal to the Po). It is, with the Rhône and Nile, one of the three Mediterranean rivers with the largest water discharge. As a result of its characteristics, the river is subject to heavy flooding. Consequently, over half its length is controlled with embankments.

The Shuttle Radar Topography Mission (SRTM) is an international research effort that obtained digital elevation models on a near-global scale from 56°S to 60°N, to generate the most complete high-resolution digital topographic database of Earth prior to the release of the ASTER GDEM in 2009. SRTM consisted of a specially modified radar system that flew on board the Space Shuttle Endeavour during the 11-day STS-99 mission in February 2000. The radar system was based on the older Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR), previously used on the Shuttle in 1994. To acquire topographic data, the SRTM payload was outfitted with two radar antennas. One antenna was located in the Shuttle's payload bay, the other – a critical change from the SIR-C/X-SAR, allowing single-pass interferometry – on the end of a 60-meter (200-foot) mast that extended from the payload bay once the Shuttle was in space. The technique employed is known as interferometric synthetic aperture radar. Intermap Technologies was the prime contractor for processing the interferometric synthetic aperture radar data.

The elevation models are arranged into tiles, each covering one degree of latitude and one degree of longitude, named according to their south western corners. For example, "n45e006" stretches from 45°N 6°E to 46°N 7°E and "s45w006" from 45°S 6°W to 44°S 5°W. The resolution of the raw data is one arcsecond (30 m along the equator) and coverage includes Africa, Europe, North America, South America, Asia, and Australia. A derived one arcsecond dataset with trees and other non-terrain features removed covering Australia was made available in November 2011; the raw data are restricted for government use. For the rest of the world, only three arcsecond (90 m along the equator) data are available. Each one arcsecond tile has 3,601 rows, each consisting of 3,601 16 bit bigendian cells. The dimensions of the three arcsecond tiles are 1201 x 1201. The original SRTM elevations were calculated relative to the WGS84 ellipsoid and then the EGM96 geoid separation values were added to convert to heights relative to the geoid for all the released products.

The Plymouth Company, officially known as the Virginia Company of Plymouth, was a company chartered by King James in 1606 along with the Virginia Company of London with responsibility for colonizing the east coast of America between latitudes 38° and 45° N.

Southernmost settlements are cities, towns, weather stations or permanent military bases which are farther south than latitude 45°S. They are closely related to the Southern Ocean or either the Roaring Forties or Furious Fifties. Antarctic bases are excluded due to not having a permanent population.

Unlike the northern hemisphere, where several major metropolitan areas such as Moscow, Harbin, London, Paris, Seattle, and Montreal are all located north of the 45°N parallel, the only permanently populated areas south of the 45°S parallel are the small and sparsely populated regions of southern Patagonia in South America, the Falkland Islands, and the southernmost tip of New Zealand.