what is the nationality of the latter?
He is Irish
Ernest Shackleton
Sir Ernest Henry Shackleton (; 15 February 1874 – 5 January 1922) was an Irish Antarctic explorer who led three British expeditions to the Antarctic.
what is farthest south? It is the most  southerly latitude reached by explorers before the conquest of the South Pole in 1911. who led the explorers? Robert Falcon Scott and Ernest Shackleton
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Ernest Shackleton [SEP] Introduction
In 1921, he returned to the Antarctic with the Shackleton–Rowett Expedition, but died of a heart attack while his ship was moored in South Georgia. At his wife's request, he was buried there.