The poles receive more direct sunshine so it has to do with the angle that the light hits. The Earth is round and when light hits it the light wraps around the earth. At the poles the light is very stretched and at the equator it is very direct hence it is hotter at the poles.
The capital of Siberia is Novosibirsk
These subs are useful in studying the ocean floor, where it is so deep that divers would be crushed by the water pressure. For example, research submersibles are used to study shipwrecks like the RMS Titanic.
