Who was the first person to set foot on all seven continents - Europe,
Asia, Africa, North America, South America, Australasia and
Antarctica?  When did they do it?

I have been unable to find your answer but you may be interested to
read these
two articles.

"Captain James Cook"; a life full of adventure, triumph, and struggle"
By: Nathan Kerl
"Cook sailed around to far reaches of the world reaching all seven
continents during his lifetime. He traveled on three very lengthy
journeys with two different sailing ships, encountering hardship and
triumph along the way."
http://members.tripod.com/cuculus/cookbio.html
Cook never landed on Antarctica.

Gavin Menzies in his first book "1421: The Year China Discovered
America."
"His book describes a giant armada commissioned by Emperor Zhu Di of
the Ming Dynasty. Hundreds of ships set sail, some of them scooting
south around Africa, poking into the Atlantic Ocean and then west to
the Pacific Ocean. They charted all seven continents. They even went
to the North Pole."
http://www.saljournal.com/stories/011903/new_china.html

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