further to ancient migrations...

Kon-Tiki was the raft used by Norwegian explorer and writer Thor Heyerdahl in his 1947 expedition. It was named after the Inca sun god, Viracocha, for whom "Kon-Tiki" was said to be an old name. Kon-Tiki is also the name of the popular book that Heyerdahl wrote about his adventures.

Heyerdahl believed that people from South America could have settled Polynesia in the south Pacific in Pre-Columbian times. His aim in mounting the Kon-Tiki expedition was to show, by using only the materials and technologies available to them at the time, that there were no technical reasons to prevent them from having done so.

Heyerdahl and a small team went to Peru, where they constucted a balsa wood raft out of balsa logs and other native materials in an indigenous style (as recorded in illustrations by Spanish conquistadores). This trip began on April 28, 1947. Accompanied by five companions, Heyerdahl sailed it for 101 days over 4,300 miles across the Pacific Ocean before smashing into the reef at Raroia in the Tuamotu Islands on August 7, 1947. The only modern equipment they had was a radio.

that was from Wikipedia:

Wolfboy notes that: While many of his conclusions are now disputed, Heyerdahl's trip proved the theory that, among other things, ancient Polynesian islanders migrated vast distances over open ocean.

The method the ancients used?

A star shaped device that taught young navigators to understand the ways that waves were directed off land masses. By learning the star's movement in the water, they learned to gauge where land was, and how far away it was.

Once they had learned this, they guided canoes over thousands of miles of open ocean by placing their hand in the water and feeling the waves.