There are holes on the poles and having hole on Arctic obviously the ocean continues on other side of the hole in inner earth.

Dimension of the holes are :inner span(center of the hole)is 95 NM wide and the diameter of the rim or the start of downward curvature is 1400 NM cca.
Earth crust close to the poles is 1050 NM thick.

Why we do not see those holes on many images from the space?
Firstly because there are not available high resolution images for great public(Google Earth etc)
Even if good photo of polar regions is seen by inexperienced eye hardly any hole will be distinguished.The center of the hole is always covered by thick cloudiness(temperature diff) and the passage of earth curvature to hole curvature is so slight that hardly visible.Example is down bellow:



and our planet's cross sections is probably as shown down bellow except that most probably the thickness of the crust in equatorial region is bigger:

Look at the design LYNN.The space is on outside and inner side of the globe so the pressure is equal.The mass of the crust has its own gravity and inner sun which definitely much denser own gravity.

In primordial time of formation of any planet there were gases and elements rotating and centripetal and centrifugal forces at work.Heavy elements remained at center forming the core,lighter elements were expulsed off that center due centrifugal force.On those lighter elements however at work also centripetal or gravity force of heavy center core.At some distance from the center those two forces were equal opposite where the lighter elements were imprisoned and formed the crust.The forces of rotation on those lighter elements were least in the axis and no elements were imprisoned there and holes were formed.

There are two great masses which produce gravity in inner earth.
The crust and it's center of gravity which is at cca one third of it's thickness.Therefor the water down the hole and in the inner earth are held by gravity perpendicular to its surface.Definitely there is an exchange of the air and the water currents through the holes.Most of the icebergs on both poles are the produce of that exchange of water currents.
The other big mass in the underworld is inner sun,which is of much bigger density and therefor gravity force, than the crust. That inner sun's gravity has it's effect on the surface of inner crust in such a way to diminish crust's own gravity in inner lands.
Holding in mind the above mentioned we have to conclude, that due to lower gravity, in inner lands everything is bigger:mountains,flora and fauna and eventual but most probable people living there.

By the way I am not SBX

mass of the crust has its gravity and pulls towards it in inner earth same as outer,just the opposite way.That inner gravity is somewhat reduced due to inner sun gravity which also partly increases the gravity on our side of the crust.Due to lesser gravity inside everything is bigger like mountains flora and fauna as well as humans from interior.

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Added on February 28, 2011, 9:16 amROBERTNGO.
there is no any polar station on Antarctica.
Actually Scott-Amundsen polar station is not on the pole but on the rim of the hole as other important station on Antarctica like McMurdo,Vostok,Winson and Weddel.


This post has been edited by CDP: Feb 28 2011, 09:16 AM