When the North and South Poles are reached by skiing from no closer than the 89° of latitude (69 miles or 111 km), this is referred to as the “last degree”. The Explorers Grand Slam can also be achieved by starting at the coast, a much longer trek.
The Seven Summits refers to the highest mountain on each continent. There are two common versions that qualify for the Seven Summits and I will attempt both:
As of 2017, 16 people are recorded as having achieved the Explorers Grand Slam by completing both versions of the Seven Summits (8 mountains) and reaching both Poles by no closer than the last degree, a total of 10 tasks. A total of 46 people have completed one or the other version (7 mountains, 9 tasks).
More information on the Explorers Grand Slam (Last Degree) can be found at http://explorersgrandslam.com or https://en.wikipedia.org/wiki/Explorers_Grand_Slam#People_who_completed_The_Explorers_Grand_Slam
TRAINING EVENTS GRAND SLAM EVENTS