Having trekked to Mount Everest base camp and reached the summits of a number of notable mountains, including five of the world's fourteen 8,000-meter peaks (Shishapangma, Everest, Cho Oyu, Manaslu, and K2), including summiting two eight thousanders back-to-back just 8 days apart (Shishapangma and Cho Oyu), O'Brien decided to build on her passion for mountaineering and set herself the challenge of achieving the Explorer's Grand Slam. The Explorer's Grand Slam entails reaching the Seven Summits, the North and South Poles, as well as meeting the Three Pole Challenge.