What geographic natural factors prevented Napoleon from conquering Russia and the United Kingdom?
The snow in Russia was a big factor. It was hard for Napoleon to
mobilize his forces through all of the snow. His forces were also
unprepared for the weather conditions. Along with this they faced
fevers and colds which put even more of a damper on his forces.
The English Channel was also a big factor in Napoleon's
conquests. It would have been an unwise move to send troops across
the English Channel when the British had one of the most superior
naval forces of their time. Sending the troops to Britain would
have been a waste of his forces.