One of the first scientific explorers was Pytheas of Massalia. He was an ancient Greek from the then Greek colony of Massalia (now Marseille). He made a voyage to northwestern Europe in about 325 BC. He circumnavigated Great Britain. Pytheas was the first person on record to describe the Midnight Sun. He is the first known scientific visitor and reporter of the Arctic polar ice. His account of the tides is the earliest known to suggest the moon as their cause.