If you're embarking on a visit to a region where you're likely to encounter extremely cold temperatures then it is vital that you dress appropriately. Temperatures at the poles are well below freezing and are low enough to kill a man from exposure rapidly. Because of this you must wear a great deal of specialised thermal clothing in order to keep warm.
Layers are vitally important, and thermal under layers should be worn beneath your clothes. Specially designed jackets and trousers that are suitable for wear in arctic conditions must be worn to in order to protect you from the extreme temperature. A face mask must also be worn, as your extremities such as your nose and ears are extremely susceptible to damage from the extreme cold.
One factor that might be over looked is sunglasses. Although it is bitterly cold in these regions sometimes the sunlight can be very bright, almost blinding, so it's important to be prepared for this. Most people who visit the arctic regions will wear a mask with goggles that have UV protection like sunglasses. These masks are dissimilar from ski masks that you might have worn if you've ever been skiing, however they are much more rugged and are adapted for use in such extreme conditions.
All this specialist clothing and equipment can be quite expensive, however it necessary in order to survive in extreme cold.