1. The Portuguese explorer Vasco da Gama hadn't seen penguins before he travelled to South Africa in 1497. 2. After he had made a pilgrimage to the city of Mecca in 1325, Ibn Battuta decided to become an explorer. 3. Many explorers had tried to climb Mount Everest before Tenzing Norgay and Edmund Hillary reached the park in 1953. 4. People in Europe hadn't eaten potatoes until Christopher Columbus brought some from America. 5. More than 400 years after Magellan had sailed around the world, the US submarine Triton made a similar journey underwater.