A helicopter tailor-made for extreme environments aids US Army rescue efforts in some of the most harsh conditions, and a trio of small but mighty tugboats move cargo vessels through the busiest port of Alaska, proving that size doesn't dictate power.

The Yeti is a custom-made snow-eater that keeps a critical Alaskan airport open for business, and experts reveal how cutting-edge engineering and the latest technology keep this machine running in the toughest conditions.