And now for a really deep topic.
The Earth's lowest known place is the Challenger Deep, almost 36,000 ft below the ocean's surface!
But however incredible it may sound, dry land also has some extreme points which lie way,
way lower than sea level.
And the lowest of them, previously hiding under a massive glacier, has been discovered
only recently!
But how about we work up to this awesome aha moment?
First, let me tell you about other, probably not so deep but no less amazing places!
- Death Valley One of the world's hottest and driest national
parks, Death Valley knows a thing or two about extremes.
Snow-covered mountain peaks in the middle of a scorching desert, burning sun - and meadows
of blooming wildflowers.
But the most amazing thing about Death Valley is that it's home to the lowest point in North
America - Badwater Basin.
This place lies 282 ft below sea level, which is just a bit smaller than the Statue of Liberty!
When you see this surreal place for the first time, you won't believe your eyes: how come
snow doesn't melt under such blazing sun?
Several moments later, you'll realize your mistake - it's not snow!
A huge chunk of the desert is covered with a thick layer of salt that's been gathering
there for centuries!
- The Dead Sea Even though it has the word "sea" in its name,
the Dead Sea is actually one of the most intriguing and unusual lakes on Earth.
You don't need any flotation device to swim in this lake - the water is so salty and dense
that its surface will keep you afloat without any effort from your side!
The Dead Sea has the highest salt concentration among all water bodies in the world and is
8 times saltier than any ocean.
The lake's made it to this list because until recently, its surface and shores were considered
the lowest point on dry land.
The Dead Sea is on average more than 1,400 ft below sea level - that's just a bit less
than the height of the Empire State Building!
And yes, I did say "until recently," and I do hope that you're thoroughly intrigued!
- Lake Baikal The next mega-deep place on land is also covered
with water because it's a freshwater lake.
The Baikal is a unique water body that contains more than 20% of all unfrozen surface freshwater
in the world.
Situated in south-eastern Siberia in Russia, Lake Baikal is also considered to be the world's
most ancient lake.
And no wonder - the thing is about 25 million years old!
The amount of water in the lake would be enough to fill the Grand Canyon five and a half times.
The Baikal's area is as large as Belgium and almost as large as Massachusetts!
The lake's total depth is more than five Eiffel Towers piled on top of each other.
And if we talk about the lake's lowest point below sea level, at 4,000 ft, it's more than
11 football fields placed side by side!
How’s that for comparison?
- The Krubera Cave No one knows for sure how deep this cave really
is.
Believe it or not but this abyss may drop down to 7,200 ft underground.
Imagine 17 Great Pyramids of Giza stacked up on top of each other, and you'll understand
why there aren't too many volunteers eager to explore the Krubera Cave!
This ancient formation is likely to be more than 5 million years old.
It's an almost vertical system of tunnels plenty of which are flooded.
That's why if you want to explore this wondrous place, remember to take your diving gear!
Even though the world's lowest natural underground point is in the Krubera Cave, it's only the
second-deepest cave on the planet.
The record-holder is the Veryovkina cave which is just one Hollywood sign deeper than the
Krubera Cave!
- Denman Glacier Antarctica's massive ice sheet effectively
hides the continent's mysteries.
But scientists don't give up: they've been using radar equipment to crack Antarctica's
riddles.
And recently, their efforts have paid off!
Previous radar instruments sent off small microwave pulses that helped researchers to
sneak a peek through the ice mass.
But this method didn't allow them to measure the full depth of some regions.
A new technology called BedMachine solved this problem.
That's when researchers made an astonishing discovery: stretching more than 11,500 feet
below sea level, a canyon under Denman Glacier turned out to be 8 times deeper than the Dead
Sea shores!
BedMachine's technology allowed scientists to combine radar readings with the information
about seismic activity and ice flows in the region and make this conclusion.
- Mponeng & TauTona Gold Mines But even though the newly-discovered canyon
under Denman Glacier is the deepest natural point on land, it doesn't mean that there
are no places deeper than that.
They DO exist, but these places were created by people, just like the two world's deepest
gold mines in South Africa.
Being almost the same in size, Mponeng and TauTona mines are as deep as 700 giraffes
and filled with complicated mazes of underground tunnels.
(uh, ‘xcuse me.
Do you really want me to say 700 giraffes?
[blah blah] Okay.)
Combined, each mine's tunnels are longer than the New York subway system – filled with
giraffes.
Thousands of workers use elevators, called cages, to get down to the mines.
These triple-decked constructions (which DO look unnervingly similar to cages) transport
more than 100 people at a time.
- By the way, few people know the mines are so deep that the rock at their bottom can
heat up to 140˚ F. To keep these underground temperatures from becoming too dangerous,
surface workers have to pump down ice mixed with salt.
When this salted ice gets into the shafts, giant fans blow air over the mixture - and
this huge DIY AC cools the tunnels down to an almost tolerable 85˚ F. To keep this complicated
system running, above-ground plants produce more than 6,000 tons of ice every day!
- KTB Borehole But even gold mining hasn't taken people as
deep as their curiosity - or should I say thirst for knowledge?
One of the lowest underground points in the world appeared thanks to a scientific drilling
project in Germany.
The main KTB borehole (that's a hole branching from the main hole) reached a mind-blowing
depth of almost 30,000 ft, which is the cruising altitude of passenger airliners – filled
with giraffes!
Down there, scorching temperatures reached 500˚F!
Luckily, drill heads used in the project could withstand up to 570˚F - otherwise, the drilling
wouldn't have been possible.
Lots of modern boreholes, though, are much longer than the KTB Borehole.
But however long they are, the world's deepest artificial point record belongs to ---drum
roll please ( bad drum roll) uh, never mind.
- SG-3 Kola Superdeep Borehole.
(boy that’s a mouthful.)
This borehole is almost 400 ft shorter than the longest man-made well.
But we're talking about the lowest points below sea level - the Kola Borehole is number
one.
The thing is 40,230 ft deep, which is twice as tall as Kilimanjaro - the world's tallest
freestanding mountain!
With a herd of giraffes on it.
The incredible borehole took about 20 years to drill.
The idea was to reach the Earth's mantle or at least drill as deep into the planet's crust
as possible.
Unfortunately, by the moment the project was closed, the hole had only reached one-third
of the way through the crust.
The site is often visited by curious sightseers but they mostly leave the place disappointed:
all there is to see is a welded borehole.
No fence around - it's unlikely that someone manages to squeeze into a 9-inch-wide hole!
In any case, come to think of it, most of the Earth's surface actually lies below sea
level because oceans cover more than 70% of our planet.
During the Ice Age, some 18,000 years ago, (I wasn’t around then), sea level was more
than 400 feet lower.
Many areas that are underwater today used to be dry land.
No one knows how much of the Earth's surface will get flooded in the future - below-sea-level
trenches and depressions may become much more impressive!
Or humans will just dig way, way deeper holes!
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