This document provides brief biographies of two famous explorers: 1) James Cook, a British explorer, navigator and captain in the Royal Navy who surveyed and mapped much of the Saint Lawrence River and later led three Pacific voyages, bringing him to the attention of the British Admiralty. 2) Yuri Gagarin, a Russian-Soviet pilot and cosmonaut who in 1961 became the first human to journey into outer space by completing an orbit of the Earth, making him an international celebrity. He later became a deputy training director but died in a 1968 plane crash.