Final answer:
Murmansk is the city on Kola Bay and the largest city within the Arctic Circle, known for its strategic military port and relatively ice-free conditions due to the North Atlantic drift.
Step-by-step explanation:
The city on Kola Bay, which is the largest city within the Arctic Circle, is Murmansk. Murmansk is renowned for being a significant military port for Russia, especially for its navy and nuclear submarine fleet. The North Atlantic drift provides warm water that circulates around Norway, which helps to keep Murmansk's port relatively free of ice, allowing it to operate more frequently compared to other northern ports, such as Arkhangelsk.
While Arkhangelsk is used primarily as a port for lumber exports, it experiences a much shorter ice-free season than Murmansk. Both cities feature long, cold winters and brief summers, characteristic of their extreme northern location.