Complex sentence: On 23 November 1964, Cunningham became the first to climb Antarctica's Mount Jackson; he was was also Station Commander of Adelaide Island in 1964-65, as well as a member of the South Georgia Survey of 1955-56.
Split into simpler sentences: On 23 November 1964, Cunningham became the first to climb Antarctica's Mount Jackson. He was was also Station Commander of Adelaide Island in 1964-65, as well as a member of the South Georgia Survey of 1955-56.