Underwater diving is the practice of descending below the water's
surface to interact with the environment. Humans are not biologically
adapted for deep diving, and must use special equipment to extend the
depth and duration of their dives. In ambient pressure diving, with
direct exposure to the pressure of the surrounding water, the diver can
use breathing apparatus for scuba diving or surface-supplied diving. For
repeated deep dives, divers can reduce the risk of decompression
sickness by living in a pressurized environment on the surface to
prevent pressurization and depressurization as they dive. Atmospheric
diving suits may be used to isolate the diver from high ambient
pressure. Diving activities are restricted to maximum depths of about 40
metres (130 ft) for recreational scuba diving, 530 metres (1,740 ft)
for commercial saturation diving, and 610 metres (2,000 ft) if
atmospheric suits are worn. The history of breath-hold diving goes back
at least to classical times, and there is evidence of prehistoric
hunting and gathering of seafoods that may have involved underwater
swimming.
Read more: <https://en.wikipedia.org/wiki/Underwater_diving>
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Today's selected anniversaries:
1862:
American Civil War: The Battle of Perryville, one of the
bloodiest battles of the war, was fought in the Chaplin Hills west of
Perryville, Kentucky.
<https://en.wikipedia.org/wiki/Battle_of_Perryville>
1897:
Composer Gustav Mahler was appointed the director of the Vienna
Court Opera.
<https://en.wikipedia.org/wiki/Gustav_Mahler>
1952:
Three trains collided at Harrow & Wealdstone station in London
killing 112 people and injuring 340.
<https://en.wikipedia.org/wiki/Harrow_and_Wealdstone_rail_crash>
1967:
Marxist revolutionary and guerrilla leader Che Guevara was
captured near La Higuera, Bolivia.
<https://en.wikipedia.org/wiki/Che_Guevara>
1998:
A new airport for Oslo, Norway, opened at Gardermoen, replacing
a smaller one at the same location that had served as a backup to the
city's previous main airport at Fornebu.
<https://en.wikipedia.org/wiki/Oslo_Airport,_Fornebu>
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Wiktionary's word of the day:
extremity:
1. The most extreme or furthest point of something.
2. An extreme measure.
3. A hand or foot.
4. A limb (“major appendage of a human or animal such as an arm, leg, or
wing”).
<https://en.wiktionary.org/wiki/extremity>
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Wikiquote quote of the day:
Bless the Maker and all His Water. Bless the coming and going of
Him, May His passing cleanse the world. May He keep the world for his
people.
--Dune
<https://en.wikiquote.org/wiki/Dune>
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